In the
 United States Court of Appeals
              For the Seventh Circuit
                        ____________

No. 04-1607
UNITED STATES OF AMERICA,
                                           Plaintiff-Appellee,

                              v.


WILLARD L. JOHNSON,
                                        Defendant-Appellant.

                        ____________
          Appeal from the United States District Court
                for the Southern District of Illinois.
         No. 02-CR-30065-01—William D. Stiehl, Judge.
                        ____________
 ARGUED SEPTEMBER 20, 2004—DECIDED FEBRUARY 1, 2005
                   ____________




  Before POSNER, KANNE, and EVANS, Circuit Judges.
  KANNE, Circuit Judge. Willard L. Johnson was convicted
after a jury trial on four counts of distributing, and one
count of possessing with intent to distribute, “cocaine base
(commonly known as ‘crack’)” within 1,000 feet of a school,
21 U.S.C. §§ 841(a)(1), 860, and sentenced to concurrent
168-month terms of imprisonment. Johnson’s sole argument
on appeal is that the district court erred in finding, for pur-
poses of applying the sentencing guidelines, that the cocaine
base he distributed was in crack form. Johnson concedes
2                                                No. 04-1607

that he stipulated at trial that drug exhibits introduced by
the government were crack, but he contends that the court
should not have relied on the stipulation at sentencing
without first specifically finding that it was knowing and
voluntary. We affirm.


                        I. History
  At trial the government introduced five exhibits contain-
ing crack. One was found on Johnson when he was arrested,
and the others were purchased from him by an informant
on four different occasions. Johnson did not dispute that
each exhibit was crack. On the contrary, he and trial coun-
sel signed a two-page stipulation separately identifying the
contents of each of these five exhibits as a specific quantity
of “cocaine base (commonly known as ‘crack’).” The govern-
ment published to the jury the corresponding portion of the
stipulation each time one of these drug exhibits was admitted
into evidence. Trial counsel declared that Johnson did not
object to any of the drug exhibits. Instead he argued that,
notwithstanding the testimony of law enforcement officers
and the informant, none of the five drug exhibits could have
come from Johnson because he sold only marijuana, not
cocaine in whatever form. The jury concluded otherwise.
  At sentencing the district court relied on Johnson’s trial
stipulation in adopting the probation officer’s recommended
finding that the drug involved in his offenses was crack.
Johnson—through new counsel appointed after trial—had
argued in a motion for new trial that the stipulation should
be disregarded because the court had not specifically deter-
mined that it was knowing and voluntary, and at sentencing
he “renewed” that argument by reference to the motion. The
court, without elaboration, denied Johnson’s objection.
No. 04-1607                                                   3

                        II. Analysis
  Johnson’s sole argument on appeal is that our decision in
United States v. Garrett, 

(7th Cir. 1999), re-
quires a sentencing court to specifically find that a stipu-
lation was knowing and voluntary before relying on it to
conclude that a substance was crack. Because the sentenc-
ing court relied on his stipulation without specifically finding
that it was knowing and voluntary, says Johnson, his guide-
line range should have been calculated using the lower base
offense level for powder cocaine, rather than the level for
crack. Johnson has made no argument that his sentence
implicates Blakely’s application to the sentencing guidelines.
See United States v. Booker, No. 04-104, 

(U.S. Jan. 12, 2005); Blakely v. Washington, 

(2004).


A. Waiver
  The government argues that Johnson waived or at least
forfeited this argument by not explicitly raising it in his
written or oral objections to the presentence report. Al-
though the question is close, on the facts here involved we
conclude that counsel’s “renewal” at sentencing of the argu-
ments included in Johnson’s motion for new trial preserved
for appeal his objection to the use of the stipulation at sen-
tencing. The reason for requiring contemporaneous objections
is to assure that district judges have the opportunity to
correct errors when they occur, see Wilson v. Williams, 

, 567 (7th Cir. 1999); United States v. Atehortua,

, 151-52 (7th Cir. 1989), and when the record
evidences that the judge understood and ruled on the objec-
tion, that purpose has been satisfied, see United States v.
Martinez, 

, 698 (7th Cir. 1993). We think it
significant that the government does not argue that the pros-
ecutor failed to understand the objection and was hampered
in responding, or that the district court was unable to grasp
4                                                No. 04-1607

the precise argument being made by Johnson. See 

Johnson’s shorthand reference to his earlier motion
for new trial was, in this particular instance, enough to alert
the district judge to his objection and preserve it for appeal.
That does not mean that it has merit.


B. Johnson misunderstands Garrett
   Garrett does not require a sentencing court to engage in
a colloquy with a defendant before relying on a stipulation
that the drug involved in the offense was crack. Defendants
regularly stipulate to facts at trial that will increase their
sentence if they are found guilty. See Harris v. United States,

, 571 (2002) (noting that drug defendants often
“enter into a stipulation before trial as to drug amounts to be
used at sentencing”); United States v. Wren, 

,
662 (7th Cir. 2004) (upholding upward adjustment in
prosecution for conspiracy to unlawfully transport firearms
in interstate commerce based on trial stipulation that
defendant supplied fifty firearms to co-conspirators); United
States v. Collins, 

, 987-88 (7th Cir. 2001) (trial
stipulation to drug quantity); United States v. Benjamin,

, 1207 (7th Cir. 1997) (trial stipulation to
drug type). And plea agreements routinely include stipula-
tions of facts relevant to sentencing. See U.S.S.G. § 6B1.4;
United States v. Cyr, 

, 100 (1st Cir. 2003) (stip-
ulation to managerial role in drug conspiracy); United States
v. Coleman, 

, 758 (7th Cir. 2003) (drug quan-
tity); United States v. Wallace, 

, 369 (7th Cir.
2002) (drug type and quantity); United States v. Bradbury,

, 201-02 (2d Cir. 1999) (offense level for con-
spiracy to commit kidnapping increased based on defen-
dant’s stipulation that conspiracy also involved marijuana
trafficking); United States v. Miller, 

, 1155
(11th Cir. 1999) (selecting offense guideline based on
defendant’s stipulation to using electronic mail to solicit
No. 04-1607                                                  5

teenagers to engage in sexual activity). We have never
required district judges to engage in a colloquy with
defendants concerning the voluntariness of stipulations or
the sentencing implications of the stipulated facts before
sanctioning a sentencing court’s reliance on the undisputed
facts. And Garrett does not create a special rule for stipula-
tions concerning crack.
   The defendant in Garrett, like Johnson, was sentenced
under the higher base offense level for crack after he en-
tered a stipulation identifying the drug he distributed as
“cocaine base (commonly referred to as 

. We vacated the defendant’s sentence, not because of
any error by the district court in accepting or applying the
stipulation, but because uncertainty in the state of the law
when the stipulation was signed made it impossible to
determine its intended meaning. 

Before 1993 the
sentencing guidelines did not define the term “cocaine
base,” and some courts interpreted the term to include not
just crack, but all forms of cocaine base. See, e.g., United
States v. Rodriguez, 

, 1378 (11th Cir. 1992);
United States v. Jackson, 

, 162 (2d Cir. 1992);
United States v. Williams, 

, 1227 (6th Cir.
1992); United States v. Pinto, 

, 49 (4th Cir. 1990);
United States v. Metcalf, 

, 46 (5th Cir. 1990). In
1993, Congress amended the guidelines to provide that “ ‘[c]o-
caine base,’ for purposes of this guideline, means ‘crack.’ ”
U.S.S.G. § 2D1.1(c)(D); see U.S.S.G. Manual, App. C, Amend.
487. In United States v. Adams, 

, 592 (7th Cir.
1997), we held that under the amended definition the higher
base offense level for “cocaine base” applies only to the rock-
like form of cocaine known on the street as “crack,” and that
the lower base offense level for “cocaine” applies to all other
forms of cocaine base, as well as cocaine powder. The parties
in Garrett entered their stipulation before we decided Adams;
thus, we were unable to determine the stipulation’s intended
meaning because, as a matter of law, “the distinction
6                                                No. 04-1607

between crack and cocaine base for purposes of sentencing
was not 

.
   Johnson, on the other hand, entered the challenged stip-
ulation almost six years after we decided Adams. Though
the language of his stipulation is virtually identical to that
of the defendant in Garrett, Johnson could not have mis-
understood its legal effect. As with other contracts, courts
interpret stipulations according to the objective intentions
of the parties. United States v. Sandles, 

, 1147
(7th Cir. 1996). Thus, we do not look beyond the four corners
of the agreement unless the stipulation is reasonably sub-
ject to more than one interpretation. See Washington Hosp.
v. White, 

, 1299-1300 (3d Cir. 1989). The phrase
“cocaine base (commonly known as ‘crack’)” was ambiguous
until we clarified the legal definitions of “cocaine base” and
“crack” in Adams. Thus, the stipulation at issue in Garrett,
because it was entered without the benefit of Adams was
capable of more than one reasonable interpretation, while
the same stipulation signed by Johnson years after Adams
is not. Because Johnson’s stipulation is clear on its face, we
do not look beyond its four corners. We interpret his
stipulation according to the objective intention of the par-
ties—that the drug involved in his offense was specifically
cocaine base in crack form.
  In Garrett we acknowledged that a “defendant’s admission
that he distributed crack, as opposed to another form of
cocaine, must be knowing and 

,
but we did not—as Johnson contends—fashion new proce-
dural hurdles that a district judge must comply with before
accepting a stipulation or relying on it as evidence at
sentencing. And plainly we did not create a special rule for
stipulations concerning crack. Rather, we merely applied
the rule for waiver—a defendant does not waive his right to
contest a court’s application of a sentencing adjustment by
admitting the existence of the adjustment’s factual predi-
cate unless his admission was “knowing and voluntary.”
No. 04-1607                                                 7

See, e.g., United States v. Wimbush, 

, 951 (7th
Cir. 2003). However, “a specific dialogue with the judge is
not a necessary prerequisite to a valid waiver” if there is
other evidence in the record demonstrating a knowing and
voluntary waiver. See United States v. Agee, 

,
886 (7th Cir. 1996) (expressly rejecting argument that
appeal waiver is valid only if accepted after colloquy with
defendant). Thus, “most waivers are effective when set out
in writing and signed.” United States v. Wenger, 

,
282 (7th Cir. 1995). Because the stipulation in Garrett was
facially ambiguous, it followed that we could not accept it as
a knowing and voluntary waiver of the defendant’s claim
that the drug he distributed was cocaine base but not crack.
But Johnson had the benefit of Adams, and we need not
look further to conclude that by entering a like stipulation,
he knowingly and voluntarily waived his right to contest
application of the higher base offense level for crack.


                     III. Conclusion
  For the foregoing reasons, we AFFIRM.


A true Copy:
       Teste:

                        ________________________________
                        Clerk of the United States Court of
                          Appeals for the Seventh Circuit




                    USCA-02-C-0072—2-1-05