United States Court of Appeals
                                                                Fifth Circuit
                                                               F I L E D
               IN THE UNITED STATES COURT OF APPEALS
                       FOR THE FIFTH CIRCUIT                   August 16, 2005

                                                            Charles R. Fulbruge III
                                                                    Clerk
                              No. 04-41129
                          Conference Calendar



UNITED STATES OF AMERICA,

                                      Plaintiff-Appellee,

versus

DARREL LYNN COWAN,
                                      Defendant-Appellant.

                      --------------------
          Appeal from the United States District Court
               for the Southern District of Texas
                     USDC No. 7:03-CR-865-1
                      --------------------

Before BENAVIDES, CLEMENT, and PRADO, Circuit Judges.

PER CURIAM:*

     Darrel Lynn Cowan pleaded guilty to one count of importing

marijuana into the United States in violation of 21 U.S.C.

§§ 952 and 960(a), (b).    The district court sentenced him to 46

months in prison, and Cowan now appeals.

     Cowan concedes that his argument that the statutes under

which he was convicted are unconstitutional because they treat

drug quantity as sentencing factors rather than elements of the

offense is foreclosed by United States v. Slaughter, 238 F.3d



     *
       Pursuant to 5TH CIR. R. 47.5, the court has determined that
this opinion should not be published and is not precedent except
under the limited circumstances set forth in 5TH CIR. R. 47.5.4.
                             No. 04-41129
                                  -2-

580, 582 (5th Cir. 2000).    He raises it only to preserve it for

further review.

     Cowan also contends that his sentence is unconstitutional in

light of the rule announced in United States v. Booker, 125 S.

Ct. 738 (2005), because the district court imposed the sentence

pursuant to the then-mandatory Federal Sentencing Guidelines,

which Booker rendered advisory.       We review for plain error.   See

United States v. Mares, 

, 520 (5th Cir. 2005),

petition for cert. filed (Mar. 31, 2005) (No. 04-9517).

Imposition of a sentence under the former mandatory guideline

regime constitutes error that is plain, i.e., obvious.       See

United States v. Martinez-Lugo, 

, 600 (5th Cir.

2005).

     We reject Cowan’s argument that such error is structural or

presumptively prejudicial with respect to whether the error

affects substantial rights, and we employ the same analysis set

forth in Mares.   See 

     As there is no indication in

the record that the district court would have given Cowan a lower

sentence under an advisory system, Cowan cannot demonstrate that

any error in the mandatory application of the Guidelines affected

his substantial rights.     See 

foregoing reasons, the judgment of the district

court is AFFIRMED.