FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,                  No. 06-50569
                Plaintiff-Appellee,           D.C. No.
               v.                        CR-02-00063-VAP-
EDWIN HERBERT ROSS,                              07
             Defendant-Appellant.
                                             OPINION

       Appeal from the United States District Court
           for the Central District of California
       Virginia A. Phillips, District Judge, Presiding

                Argued and Submitted
         December 4, 2007—Pasadena, California

                  Filed January 14, 2008

       Before: Harry Pregerson, Stephen S. Trott, and
              Richard A. Paez, Circuit Judges.

                Opinion by Judge Pregerson




                            441
                    UNITED STATES v. ROSS                   443


                         COUNSEL

Karen L. Landau, Oakland, California, for the appellant.

George S. Cardona, United States Attorney; Thomas P.
O’Brien, Assistant United States Attorney, Chief, Criminal
Division; Craig H. Missakian, Assistant United States Attor-
ney for the appellee.


                          OPINION

PREGERSON, Circuit Judge:

   Edwin Ross appeals his conviction and 188-month sentence
following a guilty plea to one count of conspiracy to distribute
more than fifty grams of cocaine base (crack), in violation of
21 U.S.C. § 841(a)(1). We have jurisdiction under 28 U.S.C.
§ 1291 and 18 U.S.C. § 3742(a). We affirm in part and
remand in part.
444                 UNITED STATES v. ROSS
                  STANDARD OF REVIEW

   We review de novo the sufficiency of a Rule 11 plea collo-
quy. United States v. King, 

, 1021 (9th Cir.
2001). A Rule 11 mistake not preserved by timely objection
below is subject to plain error review. United States v. Domin-
guez Benitez, 

, 76 (2004). We review a district
court’s denial of a motion to withdraw a guilty plea for abuse
of discretion. United States v. Davis, 

, 805 (9th
Cir. 2005). We apply a plain error standard of review to sen-
tencing errors not raised below. United States v. Ameline, 

, 1074 (9th Cir. 2005).

                        DISCUSSION

                               I.

   Ross argues that his guilty plea is invalid because the plea
colloquy did not comply with Federal Rule of Criminal Proce-
dure 11. The district court showed great patience during the
lengthy plea colloquy, which lasted more than forty minutes
and spans thirty-three pages of the record. However, the court
overlooked its regular practice of advising the defendant that
the government must prove its case beyond a reasonable
doubt. See Benchbook for U.S. District Court Judges 78 (5th
ed.) (2007) (“Ask the defendant: Do you understand . . . that
at trial you would be presumed to be innocent and the govern-
ment would have to prove your guilt beyond a reasonable
doubt[?]”).

   [1] This was error. Rule 11 provides, in part, that Ross must
understand his “right to a jury trial” and “the nature of each
charge” before his guilty plea may be accepted. See Rule
11(b)(1)(C), (G). Because the reasonable doubt standard of
proof is a due process requirement that permeates all aspects
of a criminal trial, see In re Winship, 

(1970), we
read Rule 11 as requiring an advisement of the reasonable
                         UNITED STATES v. ROSS                           445
doubt standard of proof.1 Such an advisement was particularly
necessary in this case because admission to the stated drug
quantity exposed Ross to a higher sentence. United States v.
Minore, 

, 1113 (9th Cir. 2002) (“[B]efore
accepting a guilty plea, the district court must advise the
defendant that the government would have to prove to the jury
beyond a reasonable doubt any quantity of drugs that would
expose the defendant to a higher statutory maximum sen-
tence.”); see also 21 U.S.C. § 841(b) (prescribing different
statutory maximums for violations involving various quanti-
ties of crack).

   [2] However, a Rule 11 error does not necessarily invali-
date a guilty plea. Because Ross did not object to the Rule 11
violation, the plain error standard of review applies, with its
requirement that the defendant show “a reasonable probability
that, but for the error, he would not have entered the [guilty]
plea.” Dominguez 

.

   [3] In ascertaining Ross’ understanding of the burden of
proof, we are not restricted to the record of the plea colloquy.
See United States v. Vonn, 

, 74-75 (2002). Here,
Ross acknowledged his understanding of the standard of proof
in the affidavit he filed in support of his motion to withdraw
the guilty plea. His affidavit stated, “[y]our Honor, at the time
of my plea, I thought that I could . . . have the drug amount
  1
    Other circuits have also recognized that an advisement of the reason-
able doubt standard of proof is required under Rule 11. See, e.g., United
States v. Wagner, 

, 912 (7th Cir. 1993) (“Pursuant to [Rule
11,] the court advised the defendants that . . . they would not be convicted
unless proved guilty beyond a reasonable doubt.”); United States v. Bell,

, 917 (5th Cir. 1992) (“[T]he district court engaged [the
defendant] in the requisite Rule 11 colloquy, advising him of . . . the right
to a . . . public trial by jury at which the government would have to prove
him guilty beyond a reasonable doubt . . . .”); United States v. Wade, 

, 1377 (10th Cir. 1991) (“[T]he district court followed the
requirements of Rule 11 by discussing with the defendant . . . the right . . .
to have the government prove all the elements of the offense beyond a rea-
sonable doubt . . . .”).
446                  UNITED STATES v. ROSS
proven beyond a reasonable doubt.” Moreover, Ross read and
signed a plea agreement that informed him that he was giving
up “[t]he right to be presumed innocent and to have the bur-
den of proof placed on the government to prove [him] guilty
beyond a reasonable doubt.” Because Ross knew the reason-
able doubt standard applied, he cannot establish “a reasonable
probability that, but for the [Rule 11] error, he would not have
entered the [guilty] plea,” Dominguez 

.
Accordingly, we hold that the district court’s failure to advise
Ross of the standard of proof did not constitute plain error.

                               II.

   Alternatively, Ross argues that the district court abused its
discretion when it denied Ross’ motion to withdraw his guilty
plea. Ross claims that his intention to plead guilty to conspir-
acy while retaining the right to litigate the drug quantity con-
stitutes a “fair and just reason” for withdrawing his plea under
Federal Rule of Criminal Procedure 11(d)(2)(B). He contends
that he did not understand the consequences of the guilty plea.

   [4] Ross’ statements during the plea colloquy flatly contra-
dict this claim. While under oath, he testified that he under-
stood “the consequences to [him] of pleading guilty.” During
the colloquy, Ross asked, “will there still be a hearing to
establish a factual basis in determining the drug amount[?],”
and the court informed him, “by pleading guilty, you are
agreeing to the base amount.” The government then stated the
factual basis, which alleged that Ross conspired to distribute
“approximately 290 grams of cocaine base.” The court asked
Ross, “do [you] agree with what the attorney for the govern-
ment just stated that you did in this case?,” and Ross said,
“[y]es.” When the court questioned, “[d]o you understand that
all that’s left in your case, if I accept your guilty plea, is for
you to be sentenced?,” Ross again replied, “[y]es.” Statements
made by a defendant during a guilty plea hearing carry a
strong presumption of veracity in subsequent proceedings
attacking the plea. United States v. Kaczynski, 

,
                        UNITED STATES v. ROSS                         447
1115 (9th Cir. 2001) (giving “substantial weight” to a defen-
dant’s in-court statements in determining whether a guilty
plea was voluntary); United States v. Anderson, 

, 1438 (9th Cir. 1993) (“[S]tatements made by a criminal
defendant contemporaneously with his plea should be
accorded great weight because [s]olemn declarations made in
open court carry a strong presumption of verity.”) (internal
quotation omitted).

  [5] Nor can the failure to advise Ross of the standard of
proof constitute a “fair and just reason” for withdrawal
because Ross understood that the reasonable doubt standard
applied, as reflected in the affidavit he filed and in the plea
agreement he signed — both of which are quoted above.
Accordingly, we uphold the district court’s decision to deny
Ross’ motion to withdraw his guilty plea.

                                   III.

   [6] Finally, Ross requests that this case be remanded under
United States v. Ameline, 

(9th Cir. 2005). After
Ross was sentenced, the Supreme Court decided United States
v. Booker, 

(2005). In Booker, the Court held that
the Sentencing Guidelines are advisory and that the appellate
courts should review sentences for “unreasonableness.” 

Here, the district court’s sentence was imposed at a time
when courts believed the Guidelines were a mandatory sen-
tencing regime. This constitutes plain error under Booker. See

. Accordingly, we remand for fur-
ther proceedings pursuant to Ameline.2 See 

   2
     It should be noted that the Sentencing Guidelines for crack cocaine
offenses were amended during Ross’ appeal. See Guidelines Manual
(2007), Appendix C, Amendment 706. The amendment adjusts downward
by two levels the base offense level assigned to each threshold quantity of
crack cocaine listed in the Drug Quantity Table in §2D1.1 and provides
a mechanism for determining the Guideline range for offenses involving
crack cocaine and other controlled substances. This amendment became
448                      UNITED STATES v. ROSS
   Conviction AFFIRMED; sentence REMANDED.




effective November 1, 2007, and applies to defendants sentenced on or
after that date. On March 3, 2008, time reductions for crack cocaine
offenders sentenced prior to November 1, 2007, will be authorized pursu-
ant to 18 U.S.C. § 3582(c)(2). In addition, the Supreme Court recently
held that “it would not be an abuse of discretion for a district court to con-
clude when sentencing a particular defendant that the crack/powder dis-
parity yields a sentence ‘greater than necessary’ . . . .” Kimbrough v.
United States, 552 U.S. ___ (2007).