United States Court of Appeals
                             FOR THE EIGHTH CIRCUIT
                                 ________________

                                    No. 06-3020
                                 ________________

United States of America,                  *
                                           *
           Appellee,                       *
                                           *      Appeal from the United States
      v.                                   *      District Court for the
                                           *      Northern District of Iowa.
Ricardo Watkins, also known as             *
Mac,                                       *
                                           *
           Appellant.                      *

                                 ________________

                            Submitted: January 8, 2007
                                Filed: May 29, 2007
                               ________________

Before COLLOTON and GRUENDER, Circuit Judges, and GOLDBERG, Judge.1
                        ________________

GRUENDER, Circuit Judge.

       A jury found Ricardo Watkins guilty of conspiracy to distribute or possess with
intent to distribute 50 grams or more of cocaine base in violation of 21 U.S.C.
§§ 841(a)(1), (b)(1)(A) and 846 as well as distributing less than five grams of cocaine




      1
       The Honorable Richard W. Goldberg, Judge of the United States Court of
International Trade, sitting by designation.
base in violation of 21 U.S.C. § 841(a)(1), (b)(1)(C). The district court2 sentenced
him to life in prison after denying his motion for a new trial. Watkins appeals the
denial of his motion for a new trial and his sentence. We affirm.

I.    BACKGROUND

       From at least 1996 through the fall of 1999, Watkins regularly purchased crack
cocaine from several different people in Illinois and arranged for it to be transported
to and sold in Cedar Rapids, Iowa. Watkins purchased distribution quantities of crack
cocaine at intervals varying from twice per month to twice per week, depending upon
demand. During this time, Watkins used more than ten different people to help him
cut, package, transport and sell the drugs. Christopher Winters testified that he sold
crack cocaine to Watkins several times in 1996 and regularly between the fall of 1997
and the fall of 1999. He testified that he sold between 2.25 and 4.5 ounces of crack
cocaine to Watkins on each occasion and once sold him 9 ounces of crack cocaine.
Alvin Davis testified that from the fall of 1997 into 1998 and again in 1999, he and
Watkins bought crack cocaine in Chicago and transported it to Cedar Rapids, where
they would provide the crack cocaine to others for sale on their behalf. Davis testified
that during this time period, Watkins would travel to Chicago usually twice each week
to buy 4.5 ounces of crack cocaine on each trip. Willie Herron, Dewayne Shears and
Jessica Martley all testified that they had transported crack cocaine from Chicago to
Cedar Rapids for Watkins and Davis, and Herron and Shears both sold crack cocaine
in Cedar Rapids for Watkins and Davis. In March 1998, a confidential informant
working with police in the Cedar Rapids area purchased a “rock” of crack cocaine
directly from Watkins and Davis for $100 (“the controlled purchase”).




      2
      The Honorable Linda R. Reade, Chief Judge, United States District Court for
the Northern District of Iowa.

                                          -2-
In August 1998, fearing that he was under investigation, Watkins executed a proffer
agreement with the United States Attorney’s Office for the Northern District of
Illinois (“the 1998 proffer agreement”). Watkins did not have legal counsel at the
time. The agreement allowed the Government to use Watkins’s proffered statements
against him if he “should subsequently testify contrary to the substance of the proffer,
or otherwise present a position inconsistent with the proffer.” Pursuant to the
agreement, Watkins provided incriminating information about his crack cocaine
distribution in Cedar Rapids.

       An Iowa federal grand jury indicted Watkins in October 1999 on the instant
charges, and he was arrested in March 2005 in Illinois. The district court appointed
counsel to represent Watkins. In June 2005, Watkins entered into a proffer agreement
with the United States Attorney’s Office for the Northern District of Iowa through his
counsel (“the 2005 proffer agreement”), under the terms of which he again provided
incriminating information regarding his distribution of crack cocaine in Cedar Rapids.
Watkins’s counsel believed that the 2005 proffer agreement only allowed the
Government to use the proffered statements to impeach Watkins if he were to testify.
However, the agreement actually provided that the information received during the
proffer could be used, “to impeach your client’s credibility and to focus questioning
during cross-examination; for use in a rebuttal case against your client; to develop
leads from the information provided; and for all other non-evidentiary purposes.”

        After a jury found him guilty on both counts, Watkins filed a motion for a new
trial, alleging that the jury’s verdict was contrary to the weight of the evidence and
that his counsel was ineffective. The district court held an evidentiary hearing on the
motion and created a substantial record on the ineffective assistance claims. In a
lengthy, detailed opinion, the district court denied Watkins’s motion for a new trial.
Subsequently, the district court used the United States Sentencing Guidelines to
determine an advisory sentence of life in prison based on an offense level of 43 and



                                          -3-
criminal history category of III. The district court sentenced Watkins to life in prison.
Watkins appeals the denial of his motion for a new trial and several sentencing issues.

II.   DISCUSSION

      A. New Trial

           1.       Weight of the Evidence

       We review a district court’s disposition of a motion for a new trial for an abuse
of discretion. United States v. Peters, 

, 957 (8th Cir. 2006). Where the
motion asserts that the verdict is contrary to the weight of the evidence, “the court
need not view the evidence in the light most favorable to the Government, but may
instead weigh the evidence and evaluate for itself the credibility of the witnesses.”
United States v. Huerta-Orozco, 

, 565 (8th Cir. 2001) (quotation
omitted). The district court should grant the motion only if the evidence weighs so
heavily against the verdict that a miscarriage of justice may have occurred. 

clear and manifest abuse of discretion, we uphold the district court’s ruling
on a motion for a new trial.” 

(internal quotation omitted).

      Watkins’s argument that his convictions were contrary to the weight of the
evidence focuses largely on the credibility of co-conspirator Alvin Davis’s testimony.
Davis testified pursuant to a plea agreement, hoping to receive a reduction in his own
sentence. Davis testified that from late 1997 into 1998 and again for a period in 1999,
he and Watkins purchased crack cocaine in Illinois, transported it to Cedar Rapids,
and sold it there.3 Watkins provides three examples illustrating his claim that Davis’s
testimony is unreliable. First, Davis testified that he and Watkins sold two rocks of


      3
       Davis testified that he did not associate with Watkins for a period of time
during 1998.

                                          -4-
crack cocaine to the confidential informant for $100 in the controlled purchase. (His
testimony established that he and Watkins typically sold 0.5 gram rocks of crack
cocaine for $50 each.) However, the officer involved with the controlled purchase
testified that the confidential informant purchased a single rock of crack for $100.
The confidential informant did not testify. Second, although Davis testified to the
details of the controlled purchase at Watkins’s trial in 2005, Davis claimed that he
could not recall details of the controlled purchase at his own plea hearing in 1999.
Finally, Davis testified at Watkins’s trial that he and Watkins made $1,500 to $2,000
per week selling crack cocaine, but in a proffer statement that he made in 2000, Davis
asserted that they made $1,000 to $1,500 per week. In addition, Watkins attacks the
credibility of the other co-conspirator witnesses who testified pursuant to agreements
with the Government, urging that such testimony is generally unreliable.

       While there may be some discrepancies and inconsistencies in Davis’s
testimony, these examples fall short of establishing that Watkins’s convictions were
contrary to the weight of the evidence. The testimony of seven witnesses corroborated
Davis’s central story that he and Watkins purchased significant quantities of crack
cocaine in Chicago and directed sales of crack cocaine in Cedar Rapids. The record
also demonstrates that Watkins’s counsel cross-examined all of the cooperating
witnesses, exposing details of relevant cooperation and plea agreements, and
attempted to impeach them with prior criminal convictions. See United States v.
Crenshaw, 

, 988 (8th Cir. 2004) (“Testimony does not become legally
unsubstantial because the witness stands to gain by lying; the defendant is entitled to
cross-examine such witnesses to expose their motivations, and it is up to the jury to
decide whether the witness is telling the truth despite incentives to lie.”); United States
v. Baker, 

, 798 (8th Cir. 2004) (“The fact that these witnesses testified
in exchange for the possibility of reduced sentences does not categorically make their
testimony infirm or require that their testimony be corroborated in order to support a
conviction.”). Further, in its detailed ruling on Watkins’s motion for a new trial, the
district court cited Davis’s testimony and that of the other cooperating witnesses,

                                           -5-
implicitly finding the testimony credible. See United States v. Johnson, 

,
820 (8th Cir. 2006). We have previously declined to second-guess a district court’s
credibility assessment in similar circumstances. See United States v. Judon, 

, 583 (8th Cir. 2006). Consequently, we find that the district court did not abuse
its discretion in crediting the testimony of these witnesses. The evidence adduced at
trial does not weigh so heavily against the verdict that we believe that a miscarriage
of justice may have occurred, see 

, and we affirm the
district court’s denial of Watkins’s motion for a new trial.

           2.       Ineffective Assistance of Counsel

       Although ineffective-assistance-of-counsel claims typically are best raised in
collateral proceedings under 28 U.S.C. § 2255, disposition on direct appeal is
appropriate “[w]hen the claim does not turn on information outside of the district court
record.” United States v. Staples, 

, 488 (8th Cir. 2005). In this case, the
district court conducted a full hearing on the ineffective assistance claims raised by
Watkins in his motion for a new trial, which included testimony from Watkins’s trial
counsel.

       “[W]e review the district court’s ruling on a motion for a new trial based on a
claim of ineffective assistance of counsel for abuse of discretion.” United States v.
Villalpando, 

, 938 (8th Cir. 2001). Under the Supreme Court’s well-
established standard in Strickland v. Washington, a convicted defendant must show
that counsel’s performance was deficient and that counsel’s deficient performance
prejudiced the defense. 

, 687 (1984). To show deficient performance,
“the defendant must show that counsel’s representation fell below an objective
standard of reasonableness.” 

To establish prejudice, “[t]he defendant
must show that there is a reasonable probability that, but for counsel’s unprofessional
errors, the result of the proceeding would have been different. A reasonable
probability is a probability sufficient to undermine confidence in the outcome.” 

694. “It is not enough for the defendant to show that the errors had some
conceivable effect on the outcome of the proceeding. . . . [T]he question is whether
there is a reasonable probability that, absent the errors, the factfinder would have had
a reasonable doubt respecting guilt.” 

695.

       Watkins argues first that his counsel was ineffective for failing to call Odessa
Watkins, defendant’s mother, to testify at trial. “The decision not to call a witness is
a ‘virtually unchallengeable’ decision of trial strategy . . . .” 

.
“[A] court must indulge a strong presumption that counsel’s conduct falls within the
wide range of reasonable professional assistance; that is, the defendant must overcome
the presumption that, under the circumstances, the challenged action might be
considered sound trial strategy.” 

(internal quotation
omitted). Counsel testified that he had discussed Odessa Watkins’s potential
testimony with the defendant and that they agreed not to call her to testify at trial. At
the hearing on Watkins’s motion for a new trial, Odessa Watkins testified that
although she believed that Watkins was employed in the 1997 to 1999 time frame, she
had a full-time job and could not verify his whereabouts sufficiently to exculpate him.
Further, her testimony would have corroborated trial testimony that Watkins was
acquainted with both Christopher Winters and Alvin Davis during the relevant time
period. Because Odessa Watkins’s testimony was potentially damaging and would
not have exonerated Watkins, counsel’s decision not to call her to testify at Watkins’s
trial was not objectively unreasonable. 

In any event, Odessa Watkins’s
proffered testimony is insufficient to show a reasonable probability that, but for
counsel’s decision not to call her, the outcome of the trial would have been different;
so Watkins has also failed to show prejudice. 

We therefore find no abuse
of discretion in the district court’s determination that Watkins’s counsel was not
ineffective by failing to call Odessa Watkins to testify at her son’s trial.




                                           -7-
       Watkins also argues that his counsel was ineffective for failing to call Betty
Taylor, Donjeola Barker and Marvin Lumpkins as witnesses at trial.4 Counsel’s
uncontroverted testimony was that he had never heard of these witnesses, and Watkins
does not argue that counsel should have independently discovered them. Counsel’s
failure to call these witnesses was therefore not deficient. See Battle v. Delo, 

, 1555 (8th Cir. 1994) (holding that counsel was not deficient in failing to call a
witness where the defendant never provided the witness’s name to counsel and no
evidence existed that counsel had any notice of the witness’s identity). Because
counsel’s failure to call these witnesses was not deficient, we find no abuse of
discretion in the district court’s determination that Watkins’s counsel was not
ineffective by failing to call them to testify at Watkins’s trial.

       Watkins next argues that his counsel was ineffective because he failed to
vigorously cross-examine Davis and Robert Watkins, Jr., Watkins’s brother, both of
whom testified for the Government pursuant to plea agreements. Although counsel
did cross-examine both witnesses, Watkins points out that counsel failed to impeach
Davis with his prior inconsistent statements and failed to cross-examine Robert
Watkins, Jr. about prior inconsistent statements and a particular event that might have
generated animus in him towards Watkins. Because Watkins’s counsel impeached
both witnesses with their plea agreements and felony convictions, any impeachment
with prior inconsistent statements would have been cumulative. See, e.g., Hall v.
Luebbers, 

, 694 (8th Cir. 2002). Further, Watkins’s counsel thoroughly
examined Robert Watkins, Jr. on his relationship with his brother and motivations for


      4
         Watkins argued before the district court that counsel was ineffective for failing
to call twenty other witnesses as well. Because Watkins neither names nor discusses
these twenty witnesses in his briefs on appeal, he has abandoned on appeal his
ineffective assistance claim with respect to counsel’s failure to call those witnesses.
See Fed. R. App. P. 28(a)(9)(A); United States v. Eldeeb, 

, 843 (8th Cir.
1994) (“[A] party’s failure to raise or discuss an issue in his brief is to be deemed an
abandonment of that issue.”) (quotation omitted).

                                           -8-
testifying. As the district court noted, “it is very difficult to show the trial outcome
would have been different had specific questions been asked on cross examination,”
particularly where other trial testimony repeatedly corroborated the testimony of these
two witnesses. “In hindsight, there are few, if any, cross-examinations that could not
be improved upon. If that were the standard of constitutional effectiveness, few would
be the counsel whose performance would pass muster.” Willis v. United States, 

, 1006 (8th Cir. 1996). The district court found that Watkins failed to show
prejudice arising from counsel’s cross-examination of these witnesses, and we find no
abuse of discretion in the district court’s ruling on this issue.

       Next, Watkins argues that his counsel was ineffective for failing to object to the
admissibility of the lab report which identified the rock obtained by the Government
in the controlled purchase as crack cocaine. Watkins argues that the admission of this
lab report into evidence without the testimony of its author violated his Sixth
Amendment confrontation right.5 Even if we assume for the sake of argument that
counsel’s performance was deficient and that he could have ultimately prevented the
admission of the lab report, Watkins has failed to show any prejudice. “It is well
established that the identity of a controlled substance can be proved by circumstantial
evidence and opinion testimony.” United States v. Covington, 

, 644 (8th
Cir. 1998) (internal quotation omitted). “A fact finder may rely on the observations


      5
        The district court admitted the lab report during the testimony of the police
officer involved in the controlled purchase as evidence that the rock was crack
cocaine. Though that officer submitted the rock obtained in the controlled purchase
to the lab, there is no evidence that the officer was involved in the lab testing or the
reporting of the results. Since the lab report’s author did not testify, the lab report
itself was almost certainly inadmissible hearsay. The parties’ briefs reveal nothing
regarding the absence of the lab report’s author. However, we note that the
Government’s pretrial memorandum stated that Watkins had stipulated to the
admission of the lab report. We are unable to locate in the record any such stipulation
or any indication that Watkins disagreed with the Government’s assertion that the
parties had so stipulated.

                                          -9-
of those familiar with crack cocaine when it makes findings regarding the identity of
the drug in question.” United States v. Hawthorne, 

, 405 (8th Cir. 2000).
“[W]e note that among the most knowledgeable experts on crack are those who
regularly smoke it or sell it. . . . The verdict of the marketplace is strong confirmation
that [the defendant] was selling genuine crack.” United States v. Brown, 

, 816 (8th Cir. 1998). None of the testimony adduced at trial suggested that
Watkins was dealing in forms of cocaine other than crack cocaine. One co-
conspirator testified that he smoked some of the crack that he transported on behalf
of Watkins. Another witness testified that he smoked crack cocaine obtained from
Watkins, that it was “a decent quality,” and that it gave him the same effect as other
crack cocaine he had smoked. With respect to the rock obtained during the controlled
purchase, both Alvin Davis and the officer involved identified it as crack cocaine.
There is simply no evidence to the contrary. With this record evidence, Watkins has
failed to “show that there is a reasonable probability that, but for counsel’s
unprofessional errors, the result of the proceeding would have been different.”

. Because Watkins has failed to show any prejudice arising
from the admission of the lab report, we find that the district court did not abuse its
discretion in its ruling that counsel did not provide ineffective assistance in failing to
object to its admission into evidence.

       Watkins also argues that his counsel was ineffective based on incorrect advice
regarding the consequences of the 2005 proffer agreement. At the time of the proffer,
counsel advised Watkins that the Government could only use the proffered
information against him if he testified at trial. As the language of the proffer
agreement made clear, though, the Government was entitled to use the proffered
information “in a rebuttal case against your client.” Fearing that he would open the
door to the Government’s use of Watkins’s incriminating proffer statements in a
rebuttal case, Watkins’s counsel decided not to present a witness who might have
otherwise testified on Watkins’s behalf in an effort to undermine the credibility of
three of the Government’s witnesses. The district court found that counsel’s advice

                                          -10-
about the consequences of the 2005 proffer agreement was deficient but went on to
find that Watkins failed to prove that the erroneous advice prejudiced him. The single
witness that counsel would have presented would have offered, at best, tenuous
impeachment testimony against three of the Government’s fourteen witnesses. As the
district court explained, in light of the totality of the evidence presented in the
Government’s case-in-chief, Watkins failed to establish a reasonable probability that
the outcome of his trial would have been different but for the erroneous advice. See

(holding that in determining prejudice, “a court hearing
an ineffectiveness claim must consider the totality of the evidence before the judge or
jury”). Moreover, Watkins was also subject to the 1998 proffer agreement. Like the
2005 proffer agreement, the 1998 agreement allowed the Government to use
Watkins’s proffered statements against him in rebuttal. Since Watkins’s proffered
statements under both agreements detailed his involvement selling crack cocaine in
Cedar Rapids in the late 1990s, the 1998 proffer agreement alone would have had the
same effect even without counsel’s bad advice regarding the 2005 proffer agreement.6
Because Watkins was not prejudiced by his counsel’s erroneous advice regarding the
2005 proffer agreement, we find no abuse of discretion in the district court’s ruling
on this issue.

     In sum, the district court did not abuse its discretion when it denied Watkins’s
motion for a new trial based upon claims of ineffective assistance of counsel.

      B.   Sentencing Issues

      “A sentencing court must first determine the advisory Sentencing Guidelines
range and then consider the factors set forth in 18 U.S.C. § 3553(a) to determine

      6
       Watkins argues that he did not knowingly and voluntarily enter into the 1998
proffer agreement and that he was therefore not bound by its terms. However, the
only evidence in the record shows that Watkins feared that he was under investigation
and voluntarily initiated contact with Chicago-area law enforcement that led to his
1998 proffer agreement. Consequently, we reject his argument.

                                         -11-
whether to impose a sentence under the Sentencing Guidelines.” United States v.
Lynch, 

, 995-96 (8th Cir. 2007) (internal alterations and quotation
omitted). “We review the district court’s application of the Sentencing Guidelines de
novo and its factual findings for clear error. We then review the sentence the district
court imposed for reasonableness.” 

(citations omitted).

           1.       Request for Expert Witness

       After trial but prior to sentencing, Watkins requested a court-funded expert to
perform a chemical analysis on the rock of cocaine obtained by the Government
through the controlled purchase. See 18 U.S.C. § 3006A(e). Watkins argues that the
district court erred by denying this request and that had an appointed expert succeeded
in demonstrating that the rock was not actually crack cocaine, then the district court
would have had to assess the entire drug quantity found at sentencing as powder
cocaine, which warrants a less severe advisory sentencing range than crack cocaine
under the guidelines.

       We review the district court’s refusal to appoint an expert for abuse of
discretion, and Watkins must show prejudice. United States v. Obasi, 

,
852 (8th Cir. 2006). “The defendant bears the burden of demonstrating that these
services are necessary to an adequate defense and must show a reasonable probability
that the requested expert would aid in his defense.” United States v. Mentzos, 

, 839 (8th Cir. 2006) (internal citations and quotation omitted), cert. denied,
--- U.S. ---, No. 06-10067 (Apr. 16, 2007).

       Because there is nothing in the record suggesting that the rock was anything
other than crack cocaine, Watkins has failed to show a reasonable probability that an
expert would have aided his sentencing defense. “[A] trial court need not authorize
an expenditure under [§ 3006A(e)] for a mere ‘fishing expedition’ . . . .” United
States v. Schultz, 

, 911 (8th Cir. 1970). Further, as the district court
explained, an expert could have opined only with respect to the single rock recovered

                                         -12-
by the Government from the controlled purchase. However, at sentencing the
Government sought to hold Watkins responsible for more than 1.5 kilograms of crack
cocaine on the basis of trial testimony establishing that Watkins distributed multiple
kilograms of crack cocaine over a period of several years. Thus, Watkins has also not
shown that expert testimony regarding the rock from the controlled purchase was
necessary for his defense at sentencing. Because Watkins has shown neither necessity
nor a reasonable probability that an expert would have aided his defense at sentencing,
we find that the district court did not abuse its discretion by denying Watkins’s request
for an expert.

           2.       Drug Quantity

        Watkins argues that the district court erred in computing the quantity of drugs
for which he was responsible under the sentencing guidelines. “We review a district
court’s drug quantity findings for clear error.” 

. Watkins
challenges the district court’s use of a preponderance of the evidence standard for its
factual findings at sentencing in order to preserve the issue, conceding that the
preponderance standard is proper under current Eighth Circuit precedent. See 

court may estimate drug quantities so long as the estimate is supported by a
preponderance of the evidence. 

the trial testimony, the district court
found that Watkins was responsible for, “conservatively,” 1.5 kilograms of crack
cocaine. The district court noted, “I believe it to be much higher, but I – I am
confident in that figure.” Indeed, at trial, Christopher Winters testified that in 1996,
he sold crack cocaine to Watkins six or seven times in quantities ranging from 2.25
to 4.5 ounces. This testimony supports a finding that Watkins purchased at least 13.5
ounces of crack cocaine from Winters in 1996. Winters also testified that between the
fall of 1997 and the fall of 1999, he sold crack cocaine to Watkins, again in 2.25 to 4.5
ounce quantities, “a couple times a month.” Conservatively, this supports a finding
that Watkins purchased 108 ounces of crack cocaine in that time period. Thus, the
trial testimony supports a drug quantity finding of 121.5 ounces of crack cocaine


                                          -13-
attributable to Watkins, which is equal to more than 3.4 kilograms.7 It certainly was
not clear error for the district court to attribute 1.5 kilograms of crack cocaine to him.
Under § 2D1.1(c) of the guidelines, 1.5 kilograms or more of crack cocaine warrants
a base offense level of 38.

            3.      Using a Minor To Commit a Crime

      Watkins argues that the district court erred by assessing a two-level
enhancement under § 3B1.4 of the sentencing guidelines for using a minor to commit
a crime. At trial, Willie Herron testified that he sold crack cocaine on behalf of
Watkins in 1996, when Herron was only 16 years old. The district court’s finding
based on this testimony is not clearly erroneous, and the district court properly applied
the two-level enhancement for using a minor to commit a crime in computing
Watkins’s advisory sentencing range.

            4.      Other Enhancements

       Watkins also challenges the district court’s application of guidelines
enhancements for an aggravating role in the offense under § 3B1.1 and for obstructing
justice under § 3C1.1. Watkins argues that the district court erred in finding that he
was an organizer or leader of a criminal activity that involved five or more
participants, warranting a four-level offense-level increase under § 3B1.1(a). He
argues that the district court should have found instead that he was only a manager or
supervisor under § 3B1.1(b), warranting a three-level increase. Because Watkins
concedes the three-level increase under § 3B1.1(b), his appeal of the four-level
enhancement under § 3B1.1(a) is moot. This three-level enhancement, coupled with
Watkins’s base offense level of 38 and the two-level enhancement for use of a minor,
already places Watkins at an adjusted offense level of 43. “An offense level of more
than 43 is to be treated as an offense level of 43.” U.S.S.G. Ch. 5, Pt. A, cmt. n.2

      7
       One ounce equals 28.35 grams. U.S.S.G. § 2D1.1, cmt. n.10.

                                          -14-
(sentencing table); see United States v. Saccoccia, 

, 790-91 (1st Cir. 1995)
(“It is this court’s settled practice not to address an allegedly erroneous sentencing
computation if, and to the extent that, correcting it will neither change the defendant’s
sentence nor relieve him from some unfair collateral consequence.”). For the same
reasons, Watkins’s appeal of the two-level obstruction of justice enhancement under
§ 3C1.1 is also moot.

           5.       Reasonableness

      In addition to Watkins’s challenges to the district court’s calculation of the
advisory guidelines range, Watkins argues that his life sentence is unreasonable.8
“Our review of a sentence for reasonableness is akin to our traditional review for
abuse of discretion.” United States v. Cubillos, 

, 1120 (8th Cir. 2007).

      A district court imposes an unreasonable sentence if it: “fails to consider
      a relevant factor that should have received significant weight, gives
      significant weight to an improper or irrelevant factor, or considers only
      appropriate factors but nevertheless commits a clear error of judgment
      by arriving at a sentence that lies outside the limited range of choice
      dictated by the facts of the case.”

States v. Haack, 

, 1004 (8th Cir. 2005)). The district
court made a clear and careful record of all of the sentencing factors under 18 U.S.C.
§ 3553(a) and considered each in determining Watkins’s sentence. Further, the
district court acknowledged that it had considered Watkins’s arguments for a variance


      8
       Watkins challenges the 100:1 crack-to-powder cocaine drug quantity ratio
incorporated into federal drug statutes and the guidelines as per se unreasonable. We
rejected this argument in United States v. Cawthorn, 

, 802-03 (8th Cir.
2005), petition for cert. filed, No. 05-11273 (U.S. May 25, 2006). Though Watkins
hoped that our decision in United States v. Spears, 

(8th Cir. 2006) (en
banc), petition for cert. filed, No. 06-9864 (U.S. Mar. 2, 2007), would change that
holding, it did not.

                                          -15-
based upon the § 3553(a) factors, and his brief to us on these points is taken verbatim
from his sentencing memorandum to the district court. He makes no specific
allegation of error in the district court’s § 3553(a) analysis. Our review of the record
shows that the district court considered all relevant factors, weighed them properly
and did not commit a clear error of judgment in arriving at Watkins’s life sentence,
which was within the range of choice dictated by the facts of the case. Accordingly,
Watkins’s sentence was not unreasonable.

III.   CONCLUSION

       We affirm Watkins’s convictions and sentence.

                        ______________________________




                                         -16-