                          UNPUBLISHED

UNITED STATES COURT OF APPEALS
                FOR THE FOURTH CIRCUIT


UNITED STATES OF AMERICA,              
                 Plaintiff-Appellee,
                 v.
                                                   No. 02-4590
DANIEL PROFIT DAVIS, a/k/a Daniel
Prophet Davis, a/k/a Proffit Davis,
               Defendant-Appellant.
                                       
            Appeal from the United States District Court
       for the Middle District of North Carolina, at Durham.
                James A. Beaty, Jr., District Judge.
                            (CR-01-444)

                      Submitted: January 31, 2003

                       Decided: March 11, 2003

    Before LUTTIG, WILLIAMS, and MOTZ, Circuit Judges.



Affirmed in part and dismissed in part by unpublished per curiam
opinion.


                             COUNSEL

David R. Tanis, DAVID R. TANIS, P.C., Winston-Salem, North Car-
olina, for Appellant. Anna Mills Wagoner, United States Attorney,
Robert A.J. Lang, Assistant United States Attorney, Winston-Salem,
North Carolina, for Appellee.
2                       UNITED STATES v. DAVIS
Unpublished opinions are not binding precedent in this circuit. See
Local Rule 36(c).


                              OPINION

PER CURIAM:

   Daniel Profit Davis pled guilty to an information charging that he
possessed 266.1 grams of cocaine base (crack) with intent to distrib-
ute in violation of 21 U.S.C. § 841(a), (b)(1)(A) (2000). Davis appeals
his sentence of 175 months imprisonment, challenging a two-level
weapon enhancement, U.S. Sentencing Guidelines Manual
§ 2D1.1(b)(1) (2001), the government’s failure to move for a substan-
tial assistance departure, USSG § 5K1.1, p.s., and the district court’s
decision not to depart downward on the ground that his criminal his-
tory was overstated. USSG § 4A1.3, p.s. We affirm in part and dis-
miss in part.

   Davis was arrested while he was transporting 266.1 grams of crack
and 338.4 grams of cocaine in his car. His passenger, Amos Griffin,
was carrying a firearm. Although Griffin was not charged, Davis
readily admitted that they had pooled their money to buy the drugs
and had made deliveries of drugs earlier that day. He also said that
the gun in Griffin’s possession was one he had given to Griffin for
safekeeping after an argument with its owner, but that he had told
Griffin to return it to the owner and that Griffin had specifically told
him that he had returned the gun to its owner.

   Davis argues that the weapon enhancement was not warranted
because it was not reasonably foreseeable to him that the gun was still
in Griffin’s possession and because Griffin was not charged as a co-
defendant or identified as a co-conspirator. Davis’ authority for the
latter argument is United States v. Matthews, 168 F.3d 1234, 1248 (3d
Cir. 1999) (holding that enhancement may be given for a gun pos-
sessed by someone other than the defendant only if that person is
charged as a co-conspirator). Matthews is not binding authority in this
Circuit, however, and we do not find it persuasive. Under the princi-
ple of relevant conduct, a defendant may be held accountable for the
                        UNITED STATES v. DAVIS                        3
conduct of any person involved with him in "a jointly undertaken
criminal activity," whether or nor a conspiracy is charged. USSG
§ 1B1.3(a)(1)(B), comment. (n.2). Davis acknowledged at the sen-
tencing hearing that he and Griffin were engaged in selling drugs
together.

   With respect to Davis’s first argument, we have held that a defen-
dant may be accountable for a gun possessed by another person
involved with him in a joint criminal activity without requiring that
the government establish that the defendant knew the gun was present
because the presence of weapons in such circumstances is reasonably
foreseeable. United States v. Kimberlin, 18 F.3d 1156, 1160 (4th Cir.
1994); United States v. White, 875 F.2d 427, 433 (4th Cir. 1989).
Therefore, the district court did not clearly err in making the enhance-
ment in this case. See United States v. Harris, 128 F.3d 850, 852 (4th
Cir. 1997) (standard of review).

   Next, Davis challenges the government’s decision not to move for
a substantial assistance departure despite his attempt to fully cooper-
ate. When, as here, the plea agreement does not promise a substantial
assistance motion in return for the defendant’s substantial assistance,
the defendant may compel the government to move for a substantial
assistance departure only if he makes a substantial threshold showing
that the government’s decision was based on an unconstitutional
motive or was unrelated to a legitimate government end. Wade v.
United States, 504 U.S. 181, 185-86 (1992). Although Davis did not
allege an unconstitutional motive in the district court, he now sug-
gests that he was denied due process when the government failed to
move for a departure and that he has thus met this test.

   Davis argues that the guidelines violate the separation of powers
doctrine in that the government is given the initial decision as to
whether to file a § 5K1.1 motion, which he views as a usurpation of
a judicial function. However, other circuits have held, persuasively,
that the guideline provision which requires a government motion
before the sentencing court may depart for substantial assistance does
not violate separation of powers. See, e.g., United States v. Spillman,
924 F.2d 721, 724 (7th Cir. 1991).

   Citing United States v. Martin, 25 F.3d 211 (4th Cir. 1994), Davis
also contends that he will not be able to benefit from his pre-
4                      UNITED STATES v. DAVIS
sentencing cooperation should it bear fruit in the future because Fed.
R. Crim. P. 35(b) limits a post-sentencing sentence reduction to sub-
stantial assistance provided after sentencing. However, Rule 35(b)
was amended in 1998 and now permits the court to consider pre-
sentencing assistance in evaluating a Rule 35(b) motion for sentence
reduction filed within one year after sentence is imposed. We con-
clude that Davis has not shown that the government had an unconsti-
tutional or illegitimate motive for failing to move for a departure.

   Last, Davis contends that the district court should have departed
downward from criminal history category III. The district court’s
decision not to depart is not reviewable on appeal unless the court
mistakenly believed that it lacked authority to depart. United States
v. Matthews, 209 F.3d 338, 352-53 (4th Cir. 2000). There is no doubt
that the district court knew it could depart if it believed a departure
was warranted. Therefore, this claim must be dismissed.

   Accordingly, we affirm the sentence in part and dismiss it in part.
We dispense with oral argument because the facts and legal conten-
tions are adequately presented in the materials before the court and
argument would not aid the decisional process.

                  AFFIRMED IN PART AND DISMISSED IN PART
