A Federal Criminal Law Resource — Written by a Cornell University Honors Graduate

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

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

John Kirby
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:

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:

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:

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:

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:

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
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.

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