18 U.S.C. § 3731
Section 3731 · Appeal by United States
Amended 8 times on record
The circuits are split over this section — The scope of the Government's right to appeal an adverse district-court order in a criminal case under 18 U.S.C. § 3731; Whether, for the government to take an interlocutory appeal of a pretrial suppression order under 18 U.S.C. § 3731, it must prove that the suppressed evidence is actually material to the upcoming trial, or whether the prosecutor's certification of materiality suffices.
Applied in 1,999 court decisions — leading case United States v. Marion (1971)
Most recently applied in United States v. Roberto Adams (June 2025)
Applied most in the Ninth Circuit Circuit (261 decisions)
Cases citing this section usually also cite 21 U.S.C. § 841 · 28 U.S.C. § 1291 · 18 U.S.C. § 922
How often courts cite this section
Court decisions citing this, by year.Markers show enactment, consequential amendments, and circuit splits over this section — watch for a citation surge after a change or a disagreement. The dip in the last several years is a data-coverage gap, not a real trend — our corpus holds fewer opinions from the most recent years, so recent citations are undercounted.
In a criminal case an appeal by the United States shall lie to a court of appeals from a decision, judgment, or order of a district court dismissing an indictment or information or granting a new trial after verdict or judgment, as to any one or more counts, or any part thereof, except that no appeal shall lie where the double jeopardy clause of the United States Constitution prohibits further prosecution.
An appeal by the United States shall lie to a court of appeals from a decision or order of a district court suppressing or excluding evidence or requiring the return of seized property in a criminal proceeding, not made after the defendant has been put in jeopardy and before the verdict or finding on an indictment or information, if the United States attorney certifies to the district court that the appeal is not taken for purpose of delay and that the evidence is a substantial proof of a fact material in the proceeding.
An appeal by the United States shall lie to a court of appeals from a decision or order, entered by a district court of the United States, granting the release of a person charged with or convicted of an offense, or denying a motion for revocation of, or modification of the conditions of, a decision or order granting release.
The appeal in all such cases shall be taken within thirty days after the decision, judgment or order has been rendered and shall be diligently prosecuted.
The provisions of this section shall be liberally construed to effectuate its purposes.
Editorial notes U.S. Code · Office of the Law Revision Counsel
Historical and Revision Notes
1948 Act
Based on title 18, U.S.C., 1940 ed., §682 (Mar. 2, 1907, ch. 2564, 34 Stat. 1246; Mar. 3, 1911, ch. 231, §291, 36 Stat. 1167; Jan. 31, 1928, ch. 14, §1, 45 Stat. 54; May 9, 1942, ch. 295, §1, 56 Stat. 271).
The word “dismissing” was substituted for “sustaining a motion to dismiss” in two places for conciseness and clarity, there being no difference in effect of a decision of dismissal whether made on motion or by the court sua sponte.
Minor changes were made to conform to Rule 12 of the Federal Rules of Criminal Procedure. The final sentence authorizing promulgation of rules is omitted as redundant.
1949 Act
This section [section 58] corrects a typographical error in the second paragraph of section 3731 of title 18, U.S.C., and conforms the language of the fifth, tenth, and eleventh paragraphs of such section 3731 with the changed nomenclature of title 28, U.S.C., Judiciary and Judicial Procedure. See sections 41, 43, and 451 of the latter title.
Amendments
2002—First par. Pub. L. 107–273 inserted “, or any part thereof” after “as to any one or more counts”.
1994—Second par. Pub. L. 103–322 substituted “order of a district court” for “order of a district courts”.
1986—Fifth par. Pub. L. 99–646 struck out fifth par. which read as follows: “Pending the prosecution and determination of the appeal in the foregoing instances, the defendant shall be released in accordance with chapter 207 of this title.”
1984—First par. Pub. L. 98–473, §1206, inserted “or granting a new trial after verdict or judgment,” after “indictment or information”.
Third par. Pub. L. 98–473, §205, inserted third par. relating to appeals from a decision or order, entered by a district court of the United States, granting the release of a person charged with or convicted of an offense, or denying a motion for revocation of, or modification of the conditions of, a decision or order granting release.
1971—First par. Pub. L. 91–644, §14(a)(1), enacted provision for appeal to a court of appeals from decision, judgment, or order of district court dismissing an indictment or information as to any one or more counts, except that no appeal shall lie where double jeopardy prohibits further prosecution.
Second par. Pub. L. 91–644, §14(a)(1), enacted provision for appeal to a court of appeals from decision or order of district court suppressing or excluding evidence or requiring the return of seized property in a criminal proceeding, not made after the defendant has been put in jeopardy and before the verdict or finding on an indictment or information, if the United States attorney certifies to the district court that the appeal is not taken for purpose of delay and that the evidence is a substantial proof of a fact material in the proceeding.
Such first and second pars. superseded former first eight pars. Pars. one through four had provided for appeal from district courts to Supreme Court from decision or judgment setting aside, or dismissing any indictment or information, or any count thereof and from decision arresting judgment of conviction for insufficiency of indictment or information, where such decision or judgment was based upon invalidity or construction of the statute upon which the indictment or information was founded and for an appeal from decision or judgment sustaining a motion in bar, where defendant had not been put in jeopardy. Pars. five through eight provided for appeal from district courts to a court of appeals where there were no provisions for direct appeal to Supreme Court from decision or judgment setting aside, or dismissing any indictment or information, or any count thereof and from decision arresting a judgment of conviction, and from an order, granting a motion for return of seized property or a motion to suppress evidence, made before trial of a person charged with violation of a Federal law, if the United States attorney certified to the judge who granted the motion that the appeal was not taken for purpose of delay and that the evidence was a substantial proof of the charge pending against the defendant.
Third par. Pub. L. 91–644, §14(a)(2), authorized within third par., formerly ninth, an appeal within thirty days after order has been rendered.
Fourth par. Pub. L. 91–644, §14(a), in revising the provisions, had the effect of designating former tenth par. as fourth par.
Fifth par. Pub. L. 91–644, §14(a)(3), substituted as a fifth par. provision for liberal construction of this section for prior eleventh par. provision respecting remand of case by Supreme Court to court of appeals that should have been taken to such court and treatment of the court's jurisdiction to hear and determine the case as if the appeal were so taken in the first instance and for prior twelfth par. provision respecting certification of case to Supreme Court that should have been taken directly to such Court and treatment of the Court's jurisdiction to hear and determine the case as if the appeal were taken directly to such Court.
1968—Pub. L. 90–351 inserted eighth par. providing for an appeal by the United States from decisions sustaining motions to suppress evidence and substituted in tenth par. “defendant shall be released in accordance with chapter 207 of this title” for “defendant shall be admitted to bail on his own recognizance”, respectively.
1949—Act May 24, 1949, substituted “invalidity” for “validity” after “upon the” in second par., and conformed language of fifth, tenth, and eleventh pars. to the changed nomenclature of the courts.
Savings Provision
Section 14(b) of Pub. L. 91–644 provided that: “The amendments made by this section [amending this section] shall not apply with respect to any criminal case begun in any district court before the effective date of this section [Jan. 2, 1971].”