Conspiracy Against the United States — 18 U.S.C. § 371

The 'Klein conspiracy' and defrauding the United States in its lawful functions

By John Kirby

Federal Criminal Defense Attorney • Arizona • California • Federal Courts Nationwide

2026-07-03

18 U.S.C. § 371 is a federal statute that addresses two types of criminal conspiracies against the United States: conspiracy to commit any offense against the United States and conspiracy to defraud the United States. The latter, often referred to as a Klein conspiracy after the landmark case United States v. Klein, can encompass a wide range of conduct that interferes with lawful government functions, even if no specific underlying substantive crime is committed.

Elements of 18 U.S.C. § 371 Offense Clause and Defraud Clause

The first prong of the statute, known as the offense clause, requires proof that two or more individuals agreed to commit a federal crime, took at least one overt act in furtherance of this agreement, and had an intent to achieve the illegal objective. This means you cannot be convicted under this clause without evidence of an actual criminal act being planned.

The second prong, the defraud clause, is more expansive. It does not require proof of an underlying crime; rather, it targets conspiracies that interfere with or obstruct lawful government functions. To prove a conspiracy to defraud, prosecutors must show:

• Agreement between two or more people
• An overt act in furtherance of the agreement
• Intent to defraud the United States (which can include impairing, obstructing, or defeating lawful government functions)

The breadth of this clause means that conduct which might seem benign—such as attempting to evade taxes through legal loopholes or falsifying public records—can be prosecuted under 18 U.S.C. § 371 if it undermines the integrity and proper functioning of federal agencies.

Overt Act Requirement

Both prongs of the statute include an overt act requirement, meaning that merely talking about committing a crime or defrauding the government is not enough to secure a conviction under 18 U.S.C. § 371. Prosecutors must prove that at least one conspirator took some step towards carrying out the conspiracy after the agreement was made.

Examples of overt acts include:

• Opening a bank account for laundering illicit funds
• Sending emails about how to evade taxes legally but effectively avoiding payment
• Mailing fake records or documents to a government agency

Sentencing and Penalties

The penalties for violating 18 U.S.C. § 371 can be severe, depending on the nature of the underlying offense and whether it was a substantive crime or an attempt at fraud through lawful means.

For conspiracy to commit any federal offense (offense clause), the sentence is generally no more than half the maximum for the underlying crime, with enhancements based on aggravating factors such as violence or significant financial gain. For instance:

• Tax Evasion: If tax evasion has a potential punishment of up to five years, the conspiracy to evade taxes would carry a maximum penalty of two and a half years.

The defraud clause is particularly concerning because it covers actions that might not rise to the level of an actual crime but still interfere with government functions. Sentencing here can be influenced by:

• Severity of the intended fraud or obstruction
• Impact on federal programs, services, or property
• Prior criminal history and other aggravating factors

In United States v. Klein, the Supreme Court clarified that even if the underlying substantive offense is not actually committed, attempting to defraud the government through legal means can still be prosecuted under this clause.

Practical Implications and Defense Considerations

The breadth of 18 U.S.C. § 371 means it's crucial for individuals involved in any activities that might impact federal operations or finances to understand their potential exposure to criminal charges. This includes:

• Tax Planning: Aggressive tax avoidance strategies that stretch the limits of legality can be construed as attempts to defraud the government.
• Government Contracts: Actions aimed at securing contracts through fraudulent means, even if they comply with technical legal standards, may still violate this statute.

The defense against charges under 18 U.S.C. § 371 often hinges on proving that no agreement existed to commit a federal crime or defraud the government and/or that there was no overt act in furtherance of such an agreement. It's also important to challenge whether the alleged conduct actually impaired lawful government functions.

Ultimately, navigating these waters requires careful legal representation and thorough understanding of both the specific provisions of 18 U.S.C. § 371 and the broader context of federal criminal law.

John Kirby

Cornell University Honors Graduate • Federal Criminal Defense Attorney

Licensed in Arizona, California, and federal courts nationwide. Decades of federal criminal defense experience. For direct representation, contact Kirby Criminal Law.