Second Circuit Authorizes Pre-Revocation Detention of Supervisees under 18 U.S.C. § 3143(a)(1)
Commentary on United States v. Mercado, 25-206-cr (2d Cir. Aug. 25 2025)

1. Introduction

United States v. Mercado is a seminal Second Circuit decision resolving an important procedural gap in federal supervised-release practice. The district court had concluded that, because the Non-Detention Act (18 U.S.C. § 4001(a)) forbids detention of citizens except as “pursuant to an Act of Congress,” no statute expressly authorized the pre-revocation detention of a supervisee. Reversing that view, the Court of Appeals squarely held that 18 U.S.C. § 3143(a)(1) supplies the requisite statutory authority.

Practically, the ruling settles a question that had lurked beneath many revocation proceedings: May a court detain a person who has allegedly violated supervised release before the violation is adjudicated? After Mercado, at least within the Second Circuit, the answer is yes—so long as the court applies § 3143(a)(1)’s traditional “clear-and-convincing evidence” standard and Rule 32.1(a)(6)’s procedures.

2. Summary of the Judgment

• Jurisdiction: The panel (Bianco, Lee & Nathan, JJ.) first rejected Mercado’s motion to dismiss the government’s appeal, holding that a detention order (or the denial of detention) is immediately appealable under 18 U.S.C. § 3145(c) and constitutes a “final decision” for purposes of 28 U.S.C. § 1291.
• Merits: Interpreting § 3143(a)(1)’s phrases “found guilty of an offense” and “awaiting imposition or execution of sentence,” the Court concluded that a supervisee satisfies both conditions: (1) the defendant was “found guilty” when originally convicted; and (2) once revocation proceedings commence, the defendant is “awaiting execution” of the part of the original sentence that authorizes sanctions for a breach of supervised release.
• Disposition: The district court’s contrary order was vacated and the case remanded to decide, on the facts, whether Mercado should in fact be detained under § 3143(a)(1) and Rule 32.1(a)(6).

3. Analysis

3.1 Precedents Cited

• Johnson v. United States, 529 U.S. 694 (2000) — Established that supervised release is part of the original sentence and that violations punish “breach of trust,” not new crimes.
• Mont v. United States, 587 U.S. 514 (2019) — Emphasised supervised release as “conditional liberty” and clarified tolling issues; used for definitional context.
• United States v. Haymond, 588 U.S. 634 (2019) — Recognised constitutional limits on re-imprisonment after revocation but reaffirmed that supervised-release penalties remain part of the original judgment.
• United States v. Peguero, 34 F.4th 143 (2d Cir. 2022) — Held that a defendant’s maximum exposure includes any imprisonment imposed after revocation.
• United States v. Harrison, 396 F.3d 1280 (2d Cir. 2005) & Abuhamra, 389 F.3d 309 (2d Cir. 2004) — Treated bail/detention orders as appealable final decisions.
• Second Circuit summary orders Grady and Browder — Assumed the propriety of detaining supervisees under § 3143(a)(1); Mercado converts those assumptions into binding precedent.

3.2 The Court’s Legal Reasoning

The panel’s analysis proceeds through two statutory clauses in § 3143(a)(1):

1. “Has been found guilty of an offense.”
   A supervisee’s prior conviction fully satisfies this element. The Court distinguished revocation proceedings from new prosecutions, invoking Johnson and Peguero to emphasise that all supervised-release consequences flow from the original judgment. Therefore, reliance on the underlying conviction does not run afoul of double-jeopardy doctrines: revocation sanctions are not a second punishment for the same crime but a consequence for violating an existing condition of sentence.
2. “Is awaiting … execution of sentence.”
   Because the sentence imposed in 2015 already contemplated a potential revocation prison term (via § 3583(e)(3)), initiating revocation puts the defendant in an “awaiting execution” posture with respect to that component. The Court rejected the district court’s narrower reading that only a yet-to-be-imposed sentence can be “awaiting execution.” Finality attaches upon imposition of sentence, not upon its execution.

Having satisfied both prongs, the defendant falls squarely within § 3143(a)(1). Rule 32.1(a)(6) then imports the usual release-pending-sentence standard: release is permissible only if the court finds by clear and convincing evidence that the person is neither a flight risk nor a danger.

3.3 Impact and Prospective Significance

1. Uniform Detention Standard. District courts within the Second Circuit now possess explicit authority to detain supervisees during violation litigation, eliminating the uncertainty that surfaced in the district court’s opinion (and occasionally elsewhere).
2. Reconciling the Non-Detention Act. By locating clear statutory authority in § 3143(a)(1), the panel effectively harmonises the Non-Detention Act with routine supervised-release practice, forestalling similar challenges.
3. Influence on Other Circuits. While other circuits had assumed the authority, Mercado is the first to confront and analyze the Non-Detention Act argument head-on. Expect sister circuits either to cite Mercado approvingly or to address the question in their own published opinions.
4. Strategic Decisions by Counsel. Defense attorneys may now focus less on “authority” objections and more on the merits under § 3143(a)(1)—i.e., demonstrating lack of danger or flight risk by clear and convincing evidence.
5. Sentencing Philosophy. The decision reinforces the conceptual unity of imprisonment and supervised release as a single sentencing package, further entrenching the view that revocation is part of the original punishment continuum.

4. Complex Concepts Simplified

• Non-Detention Act (18 U.S.C. § 4001(a))
  A broad civil-liberties statute providing that no U.S. citizen may be detained except under an Act of Congress. Courts must therefore identify a clear statutory basis anytime they incarcerate a citizen.
• Supervised Release
  A post-prison period during which the defendant lives in the community subject to court-imposed conditions (much like federal “parole,” which it replaced). Violations can result in additional imprisonment.
• Revocation Proceedings
  Non-jury hearings where the judge decides, by a preponderance of the evidence, whether a supervisee breached a condition and what sanction—up to the statutory cap—should follow.
• 18 U.S.C. § 3143(a)(1)
  The Bail Reform Act provision governing whether a convicted defendant may be released while awaiting sentencing or execution of sentence. Release is allowed only if the defendant proves (by clear and convincing evidence) no flight risk and no danger.
• Final Order under 28 U.S.C. § 1291
  Generally, appeals lie only from “final decisions.” A detention or release order is treated as “final” for this limited purpose because § 3145(c) so provides and because the issue would otherwise evade review.

5. Conclusion

United States v. Mercado crystallises a principle that had been widely assumed but never articulated in a precedential Second Circuit opinion: a district court may detain a supervisee pending revocation hearings under § 3143(a)(1) without violating the Non-Detention Act. By reading “found guilty of an offense” to reference the original conviction and “awaiting execution of sentence” to encompass the yet-to-be-determined revocation sanction, the Court harmonises the Bail Reform Act, supervised-release statutes, and constitutional safeguards. The decision provides a clear roadmap for judges and practitioners: invoke § 3143(a)(1), apply the clear-and-convincing standard, and conduct hearings under Rule 32.1(a)(6). Going forward, Mercado will likely be cited whenever litigants raise statutory or constitutional objections to pre-revocation detention, solidifying its place in the supervised-release jurisprudence of the federal courts.