United States Court of Appeals
                            FOR THE EIGHTH CIRCUIT
                                    ___________

                                    No. 02-3642
                                    ___________

United States of America,                *
                                         *
             Appellee,                   *
                                         * Appeal from the United States
      v.                                 * District Court for the
                                         * Eastern District of Missouri.
Felipe Lothridge,                        *
                                         *
             Appellant.                  *
                                    ___________

                              Submitted: March 13, 2003

                                   Filed: April 4, 2003
                                    ___________

Before BOWMAN, MORRIS SHEPPARD ARNOLD, and RILEY, Circuit Judges.
                         ___________

BOWMAN, Circuit Judge.

      Felipe Lothridge was convicted of possession with intent to distribute cocaine
base. See 21 U.S.C. § 841(a)(1) (2000). On appeal, he raises three issues, urging that
the District Court erred when it denied his motion to suppress, when it admitted
evidence of his prior bad acts, and when it admitted the drugs into evidence despite
Lothridge's proffered evidence of tampering. We have no occasion to reach the
merits of Lothridge's claims because the District Court erred when it failed to conduct
a de novo review of the magistrate judge's proposed findings regarding Lothridge's
motion to suppress, insofar as Lothridge objected to those findings. Accordingly, we
remand the matter to the District Court for the required de novo review.
       Under 28 U.S.C. § 636(b)(1) (2000), district courts may designate magistrate
judges to conduct, inter alia, evidentiary hearings on suppression motions and to
submit to a district judge proposed findings of fact and recommendations for the
disposition of the matter. Section 636(b)(1) also requires that when a party objects
to the report and recommendation of a magistrate judge concerning a dispositive
matter, "[a] judge of the court shall make a de novo determination of those portions
of the report or specified proposed findings or recommendations to which objection
is made." Id.; see also Fed. R. Civ. P. 72(b). We have repeatedly observed that
failure to engage in the required de novo review is reversible error. See, e.g., Hudson
v. Gammon, 

, 786 (8th Cir. 1995). This is so because unless the ultimate
decision is made by a district judge, Article III power has effectively been exercised
by a magistrate judge, see United States v. Raddatz, 

, 677-78 (1980), and
magistrate judges, who are appointed by district courts, for limited terms of office,
are not Article III judges. The exercise of ultimate judicial authority by other than
Article III officers affects both individual and structural constitutional protections.
In terms of individual protections, the defendant's right to be tried by an Article III
judge is implicated. Peretz v. United States, 

, 936-37 (1991). From an
institutional standpoint, allowing a magistrate judge to exercise Article III power may
impugn the structural protections inherent in our tripartite system of government. See
Commodity Futures Trading Comm'n v. Schor, 

, 850 (1986). Although
Lothridge does not raise the issue on appeal, because of our institutional concerns,
his waiver, whether inadvertent or intentional, does not affect our ability to notice the
District Court's failure to conduct a de novo review.

      In general, we presume that a district judge has in fact undertaken a de novo
review of the disputed portions of a magistrate judge's report and recommendations
regarding a dispositive issue. See, e.g., Jones v. Pillow, 

, 253 (8th Cir.
1995). This presumption is unwarranted if it affirmatively appears that the district
judge has not applied the de novo standard. 

is here. Although the District
Court initially identified the proper standard of review, it subsequently stated that

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"[t]he magistrate judge's determination of credibility is entitled to great weight."
Memorandum and Order at 4 (June 4, 2002) (citing Vekamaf Holland B.V. v. Pipe
Benders, Inc., 

, 611 (8th Cir. 1982)). It further stated that "[t]he factual
findings made by the magistrate judge in determining credibility 'shall not be set aside
unless clearly erroneous.'" 

States v. Risken, 

, 1100
(8th Cir. 1989) and Dumond v. Lockhart, 

, 420 (8th Cir. 1989)). The
District Court then concluded that it could not say that the magistrate judge's
"credibility findings are clearly erroneous. Thus, the defendant's objections will be
overruled." 

the cases cited by the District Court stand for the proposition
that a district judge can defer to a magistrate judge's findings on credibility. In
Dumond, the parties consented to have the petition for a writ of habeas corpus heard
before a magistrate judge pursuant to 28 U.S.C. § 636(c)(1) and the appeal from the
judgment entered by the magistrate judge was directly to this 

.
We thus reviewed the case under our normal standard of review as if it had been
heard by a district judge. In Risken, we considered an appeal from a district judge's
denial of a writ of habeas 

. No magistrate judge was
involved.

      Nor does Vekamaf Holland B.V. ("Vekamaf II") authorize district-court
deference to credibility findings made by a magistrate judge. Our statement in
Vekamaf II that "[w]e agree with the district court that the magistrate's determinations
of credibility are entitled to great weight on appeal" is properly understood only
within the context of that 

. In Vekamaf, the case was tried, with
the consent of the parties, to a magistrate judge sitting as a special master pursuant
to 28 U.S.C. § 636(b)(2) and Federal Rule of Civil Procedure 53. Vekamaf Holland

      1
       Under 28 U.S.C. § 636(c), the parties to a civil lawsuit may consent to have
their case tried before a magistrate judge, with or without a jury. The judgment
entered by the magistrate judge is the judgment of the district court and may be
appealed to the court of appeals "in the same manner as an appeal from any other
judgment of a district court." 

636(c)(3).

                                          -3-
B.V. v. Pipe Benders, Inc., 

, 1186 (8th Cir. 1982). Solely within the
context of a referral to a special master (whether a magistrate judge or not), Rule
53(e)(2) specifies that in non-jury actions, the district court "shall accept the master's
findings of fact unless clearly erroneous." See also Calvin Klein Cosmetics v.
Parfums de Coeur, Ltd., 

, 670 (8th Cir. 1987). We hasten to add that a
district judge is still bound to make a de novo review of the special master's
conclusions of law. See Cook v. Niedart, 

, 1010 (7th Cir. 1998) ("a
district court reviews a special master's legal conclusions de novo and accepts
findings of fact unless they are clearly erroneous" (citations omitted)); Charles A.
Wright & Arthur R. Miller, Federal Practice and Procedure § 2614 (2d ed. 1994 &
2002 Supp.). In sum, the clearly erroneous standard that we identified in Vekamaf II
applies to review of matters in non-jury cases that are referred to a special master and
not to the review of objected-to findings in a report and recommendation made by a
magistrate judge to a district judge, as in the case at hand.

      Because the District Court did not conduct a de novo review of the objected-to
matters in the magistrate judge's report and recommendation and did not make its own
findings as to those matters, we remand this case to the District Court for the limited
purpose of conducting the required de novo review. We retain jurisdiction over this
appeal. Within thirty days from the issuance of this opinion, the District Court shall
conduct the required de novo review and shall certify to this Court its findings of fact
and conclusions of law.

      A true copy.

             Attest:

                 CLERK, U.S. COURT OF APPEALS, EIGHTH CIRCUIT.




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