A Queen for a Day agreement is the informal name for a federal proffer agreement: a written contract between a prosecutor and someone under investigation that lets the person sit down with the government, answer questions, and receive one narrow promise in return. The government agrees not to use the person’s own statements from that session as direct evidence of guilt in its case-in-chief at trial. That is the entire headline protection. It is not immunity, it is not a plea deal, and it does not stop the government from prosecuting you using leads your statements generate.
What the Agreement Actually Promises
The core promise is limited and worth stating precisely. The government generally cannot introduce your own words from the proffer session as direct evidence during its case-in-chief at trial. Everything else about how prosecutors can use what you say is governed by the exceptions and waivers in the written agreement, which is why the fine print matters far more than the headline.
Your defense attorney negotiates the written terms before you say anything. Once the letter is signed, you meet with the assigned prosecutor and one or more federal agents, usually at a prosecutor’s office or federal building. The government’s purpose is to evaluate whether your information is useful enough to justify a formal cooperation agreement or a favorable plea. The proffer itself is the audition.
The Protection Is Narrower Than Most People Assume
Federal law recognizes two kinds of statutory immunity. Transactional immunity shields a person from any prosecution related to the testimony. Use-and-derivative-use immunity under 18 U.S.C. § 6002 bars the government from using the compelled testimony or any evidence “directly or indirectly derived from such testimony” against the witness in a criminal case, except for perjury or false statements.1Office of the Law Revision Counsel. 18 U.S.C. 6002 – Immunity Generally If the government later prosecutes someone who received statutory use immunity, it carries the burden of proving that every piece of its evidence came from a source wholly independent of the immunized testimony.2Justia Law. Kastigar v. United States, 406 U.S. 441 (1972)
A proffer agreement provides neither form of immunity. It strips away the derivative-use protection in particular. The government promises not to play your words back to a jury as direct evidence, but it keeps the right to follow every lead those words generate. If you point prosecutors to a document, name a witness they did not have, or describe how a scheme operated, they can chase all of it and use whatever they find, including against you. This derivative-use provision appears in virtually every federal proffer agreement, and it is the single most important risk people overlook.
The Rule 410 Waiver You Sign
Federal Rule of Evidence 410 was written to encourage open plea negotiations by making statements during plea discussions generally inadmissible against the defendant.3Legal Information Institute (LII) / Cornell Law School. Federal Rules of Evidence Rule 410 – Pleas, Plea Discussions, and Related Statements Federal Rule of Criminal Procedure 11(f) reinforces that protection by tying admissibility of plea-related statements directly to Rule 410.4Legal Information Institute (LII) / Cornell Law School. Federal Rules of Criminal Procedure Rule 11 – Pleas
If those protections applied to proffers by default, prosecutors would have very limited ability to use anything said during the session. So every standard proffer agreement requires you to waive Rule 410. In United States v. Mezzanatto, the Supreme Court held that this waiver is enforceable so long as the agreement is entered into knowingly and voluntarily.5Legal Information Institute (LII) / Cornell Law School. United States v. Mezzanatto, 513 U.S. 196 (1995) You are surrendering a protection Congress created for your benefit, and taking a much narrower contractual promise in return.
When the Government Can Still Use What You Said
Even the narrow direct-use bar has well-defined exceptions, and prosecutors enforce them aggressively.
Impeachment and Rebuttal
If you go to trial and testify in a way that contradicts what you said during the proffer, the government can introduce your proffer statements to undermine your credibility. The same applies if your defense team presents evidence or arguments that conflict with facts you disclosed. The proffer effectively locks in your version of events; change your story later and the government has a ready-made weapon.
Breach of the Agreement
Lying during a proffer is catastrophic. If the government determines you provided false or misleading information, the agreement’s protections evaporate and everything you said becomes available for direct use against you. You also face potential charges for making false statements under 18 U.S.C. § 1001, which carries up to five years in federal prison.6Office of the Law Revision Counsel. 18 U.S.C. 1001 – Statements or Entries Generally Obstruction charges are also on the table. The proffer room is not a place to shade the truth or test what the government already knows.
Sentencing
Many proffer agreements permit the government to use your statements during sentencing if you are ultimately convicted. Sentencing operates under different evidentiary rules than trial, so statements that are off-limits in front of a jury may be fair game when a judge decides your sentence.
Inside the Session
The session is attended by you, your defense attorney, the prosecutor, and investigating agents. Your attorney typically opens with a brief statement framing the topics you will address. Prosecutors and agents then take over with questions ranging from broad (“tell us everything you know about X”) to granular (“who was in the room when this happened?”). If a question is uncomfortable or you are uncertain, you can step out to consult privately with your attorney, and that request is always honored.
The expectation is candor. Evasiveness or obvious withholding signals that you are not a reliable cooperator and can end any hope of a deal. Sessions have no set length. Some run a couple of hours; complex financial investigations stretch across multiple meetings over weeks.
What Happens If No Deal Materializes
Standard proffer agreements explicitly state that the session is not a cooperation agreement and creates no obligation for the government to offer one. If prosecutors decide your information is not valuable enough, or that you were not fully forthcoming, the proffer simply ends.
You have now given the government a roadmap of what you know, who you dealt with, and how the alleged conduct worked. Prosecutors cannot replay your words at trial, but they can follow every lead you handed over. They know which documents to subpoena, which witnesses to interview, and which transactions to scrutinize, because you told them. The government remains free to prosecute you using independently obtained evidence, including evidence it discovered by chasing those leads. Defense attorneys describe this as the central gamble of any proffer: if it does not lead to a cooperation agreement, you may have done the prosecution’s investigation for them.
The Payoff When Cooperation Succeeds
When a proffer leads to a formal cooperation agreement, the potential rewards are substantial. Federal sentencing law provides two main mechanisms.
Under U.S. Sentencing Guidelines § 5K1.1, the government can file a motion certifying that the defendant provided substantial assistance in investigating or prosecuting someone else. The motion lets the judge depart downward from the guideline range and impose a sentence below a mandatory minimum.7United States Sentencing Commission. The Use of USSG 5K1.1 – Substantial Assistance Departures For defendants facing lengthy mandatory minimums, a 5K1.1 motion can mean the difference between decades in prison and a manageable sentence.
If cooperation continues after sentencing, the government can file a motion under Federal Rule of Criminal Procedure 35(b) asking the court to reduce a sentence already imposed. A Rule 35(b) motion must generally be filed within one year of sentencing, with exceptions when the defendant’s information did not become useful until later.8United States Sentencing Commission. The Use of Federal Rule of Criminal Procedure 35(b) Like a 5K1.1 departure, a Rule 35(b) reduction can go below both the guideline range and a mandatory minimum.
Both mechanisms share one critical feature: only the government can file the motion. The defendant cannot ask the court for a substantial-assistance reduction on their own. If prosecutors decide your cooperation was not valuable enough, the judge’s hands are tied no matter how much information you provided.
Deciding Whether to Proffer
Whether to accept a proffer is one of the highest-stakes decisions in federal criminal defense, and the answer is not always yes. A proffer makes the most sense when you have genuine criminal exposure and meaningful information about others involved. If the government is likely to charge you regardless, cooperating early, before they build the case themselves, gives you the strongest bargaining position. The information you offer is worth the most when prosecutors need it the most. Wait too long and someone else in the conspiracy may proffer first, leaving you with nothing to trade.
If you are a peripheral figure and the government may not have enough to charge you independently, a proffer carries significant downside. You might be handing investigators the leads they need to build a case against you. Where exposure is genuinely uncertain, asking for statutory immunity under 18 U.S.C. § 6002 may be worth pursuing, though prosecutors grant formal immunity far less readily than they offer proffer letters.
Accidental false statements deserve special attention. Memory is imperfect, especially in complex financial matters or events that happened years ago. If you misstate a date, misremember who was present, or characterize a conversation differently than a recording later shows, the government may treat that as a breach. Experienced defense attorneys prepare clients extensively before a session, reviewing documents and walking through timelines to minimize the chance that an innocent mistake looks like dishonesty.
Proffer agreements are overwhelmingly a federal practice, and they reflect a system where most convictions come from plea deals rather than trials. The proffer is often the gateway to those deals. Decline it and later try to negotiate a plea, and you will typically bargain from a weaker position, because the government has never had the chance to verify what you know.