The U.S. Attorney's Role in Federal Criminal Cases

United States Attorneys serve as the chief federal law enforcement officers within their respective judicial districts, representing the federal government in both criminal prosecutions and civil litigation. The United States is divided into 94 federal judicial districts, each served by a presidentially appointed U.S. Attorney (U.S. Department of Justice, USAO Overview). This page covers the statutory authority, prosecutorial functions, charging decisions, and jurisdictional boundaries that define the U.S. Attorney's role in federal criminal cases.

Definition and Scope

U.S. Attorneys derive their authority from 28 U.S.C. § 547, which directs each U.S. Attorney to prosecute all offenses against the United States and to conduct civil and criminal proceedings on behalf of the government within their district. Appointment is governed by 28 U.S.C. § 541, requiring presidential nomination and Senate confirmation. Each U.S. Attorney operates within the Department of Justice (DOJ) under the supervision of the Attorney General and reports through the Executive Office for United States Attorneys (EOUSA).

The scope of federal criminal jurisdiction — and therefore U.S. Attorney authority — extends to offenses defined in Title 18 of the United States Code (the principal federal criminal code), as well as criminal provisions scattered across Title 21 (controlled substances), Title 26 (tax offenses), Title 31 (financial crimes), and other federal statutory titles. For a detailed breakdown of how federal jurisdiction differs from state authority, see Federal vs. State Criminal Jurisdiction.

U.S. Attorneys lead offices staffed by Assistant U.S. Attorneys (AUSAs), who conduct the day-to-day work of prosecution. As of the DOJ's most recent organizational reporting, USAO offices collectively employ more than 5,600 AUSAs across the 94 districts (EOUSA, FY 2023 Performance Budget). The U.S. Attorney themselves typically focuses on district-wide policy, resource allocation, and high-profile matters.

How It Works

The federal prosecution process proceeds through distinct phases, each involving a defined U.S. Attorney function:

1. Investigative coordination. Federal investigations are conducted by agencies such as the FBI, DEA, ATF, IRS Criminal Investigation, or Homeland Security Investigations. U.S. Attorneys and AUSAs work in parallel with these agencies, advising on legal sufficiency and evidentiary standards before charges are filed.

2. Charging decision. After reviewing investigative materials, the AUSA determines whether to seek charges. This decision is governed internally by the DOJ Justice Manual (JM) § 9-27.000, the Principles of Federal Prosecution. These principles require that charges be filed only when there is probable cause and a reasonable probability of conviction at trial, and that the charges selected adequately reflect the seriousness of the offense.

3. Grand jury presentation. For felony charges, the Fifth Amendment requires presentation to a grand jury, which determines whether probable cause supports an indictment. AUSAs present evidence to the grand jury and subpoena witnesses.

4. Arraignment and pretrial proceedings. After indictment, the defendant is brought before a federal magistrate or district judge for arraignment, where charges are formally read and a plea is entered.

5. Plea negotiation or trial. The majority of federal cases resolve through plea agreements rather than trial. DOJ data consistently shows that plea agreements resolve roughly 90 percent of federal convictions (U.S. Sentencing Commission, 2022 Annual Report).

6. Sentencing advocacy. At sentencing, AUSAs present the government's sentencing position, typically calculated using the U.S. Sentencing Guidelines as the framework, and may recommend upward or downward departures.

7. Post-conviction proceedings. U.S. Attorney offices handle government appeals, responses to habeas petitions, and supervised release revocation proceedings.

Common Scenarios

U.S. Attorney offices handle a broad range of federal criminal matters. The most frequently prosecuted categories include:

• Drug trafficking offenses under 21 U.S.C. § 841 and related statutes — historically the largest single category of federal prosecutions, representing approximately 28 percent of cases sentenced in fiscal year 2022 (U.S. Sentencing Commission, 2022 Sourcebook).
• Immigration offenses, including illegal reentry under 8 U.S.C. § 1326, which constituted roughly 30 percent of sentenced federal cases in fiscal year 2022 (U.S. Sentencing Commission, 2022 Sourcebook).
• White-collar crimes including wire fraud (18 U.S.C. § 1343), bank fraud (18 U.S.C. § 1344), and money laundering (18 U.S.C. § 1956).
• Weapons offenses under 18 U.S.C. § 922 and § 924, including felon-in-possession and use of a firearm during a crime of violence.
• Cybercrime prosecutions under the Computer Fraud and Abuse Act (18 U.S.C. § 1030) and related statutes.
• RICO and criminal conspiracy cases targeting organized criminal enterprises.

The distribution of case types varies significantly by district. Border districts such as the Southern District of Texas and the District of Arizona handle a disproportionate volume of immigration and drug trafficking cases, while districts containing major financial centers prosecute a higher concentration of securities fraud and white-collar matters.

Decision Boundaries

The U.S. Attorney's charging authority is broad but bounded by several structural constraints:

Constitutional limits. Charges must comport with due process requirements under the Fifth Amendment and be supported by probable cause. The grand jury serves as a constitutional checkpoint against unfounded felony charges.

DOJ Principles of Federal Prosecution. The Justice Manual § 9-27.000 prohibits charging decisions motivated by improper factors such as race, religion, sex, national origin, or political association. Prosecutors must select the most readily provable charges that adequately reflect the conduct — not simply the charges carrying the highest penalty.

Declination vs. prosecution. U.S. Attorneys retain discretion to decline prosecution even where sufficient evidence exists, particularly when federal prosecution would duplicate state proceedings, when resources are better directed elsewhere, or when the offense is more appropriately handled at the state level. This is a key distinction from state prosecutors, whose offices are typically required to prosecute upon referral from law enforcement. For more on how federal and state prosecution systems compare, see Federal Criminal Law vs. State Criminal Law.

Cooperation agreements and plea authority. AUSAs may enter into cooperation agreements whereby defendants provide substantial assistance to the government in exchange for a motion under USSG § 5K1.1, enabling a sentence below the applicable Guidelines range. These agreements require supervisory approval within the USAO and, in some cases, DOJ Main Justice sign-off.

Mandatory minimums and statutory constraints. While U.S. Attorneys have discretion in charging, certain statutes — particularly drug quantities that trigger mandatory minimum sentences under 21 U.S.C. § 841(b) — constrain the sentencing outcomes available to the court once specific charges are filed. The decision to charge a quantity-specific drug count is therefore also a decision about the minimum sentence the judge must impose upon conviction.

References

• U.S. Department of Justice — United States Attorneys Overview
• 28 U.S.C. § 541 — Appointment of United States Attorneys
• 28 U.S.C. § 547 — Duties of United States Attorneys
• DOJ Justice Manual § 9-27.000 — Principles of Federal Prosecution
• Executive Office for United States Attorneys (EOUSA)
• [U.S. Sentencing Commission — 2022 Annual Report and Sourcebook](https://www.ussc.