In the United States v. Citroen case of 1911, the Supreme Court examined whether a federal court had jurisdiction over an action brought by a foreign corporation against another foreign corporation and U.S. citizens for alleged conspiracy to defraud it in violation of state law. The plaintiff was a French automobile manufacturing company that claimed defendants conspired to fraudulently induce it into entering contracts which resulted in financial loss. The defendants argued that since both corporations were incorporated under French law, the dispute should be resolved there rather than in U.S courts. The Supreme Court held that federal courts did have jurisdiction over such cases if diversity of citizenship existed between parties and if other requirements for subject matter jurisdiction were met (such as meeting minimum amount-in-controversy). However, they also noted that even when these conditions are satisfied, courts may exercise discretion not to hear cases involving complex issues of foreign law or where adjudication would be more appropriate in another forum - principles known as "forum non conveniens." In this particular case though, because some conspiratorial acts occurred within the US and involved American citizens who could not easily litigate abroad, it was deemed appropriate for US federal court involvement.

The dissenting opinion in the United States v. Citroen case argued that the majority's decision to uphold a conviction for conspiracy to defraud the government was incorrect because it relied on an overly broad interpretation of what constitutes a "conspiracy." The dissent contended that there must be proof of an actual agreement between two or more parties to commit an illegal act, and not just evidence of separate acts by individuals who may have had similar objectives. It also disagreed with the majority's view that mere knowledge or approval of another person’s fraudulent actions could constitute participation in a conspiracy. The dissent further criticized the majority for allowing circumstantial evidence alone as sufficient proof for establishing guilt beyond reasonable doubt, arguing this lowered standard would lead to potential abuses and wrongful convictions.