United States v. Rocha was a United States Supreme Court case that dealt with the issue of whether a Mexican citizen who had been convicted of a crime in Mexico could be extradited to the United States to face criminal charges. The case arose when the United States government sought to extradite a Mexican citizen, Francisco Rocha, to face criminal charges in the United States. Rocha argued that he was not subject to extradition because he was a Mexican citizen and the extradition treaty between the United States and Mexico did not apply to Mexican citizens. The Supreme Court held that the extradition treaty between the United States and Mexico did apply to Mexican citizens, and that Rocha could be extradited to the United States to face criminal charges. The Court reasoned that the treaty was intended to apply to all persons, regardless of their nationality, and that the treaty did not make any distinction between citizens and non-citizens. The Court also noted that the treaty was intended to promote international comity and cooperation between the two countries, and that allowing extradition of Mexican citizens would further this goal. In conclusion, the Supreme Court held that the extradition treaty between the United States and Mexico did apply to Mexican citizens, and that Francisco Rocha could be extradited to the United States to face criminal charges. The Court's decision was a significant step in promoting international comity and cooperation between the two countries.

In United States v. Rocha, the Supreme Court was asked to decide whether a Mexican citizen who had been living in California since before it became part of the United States could be convicted of murder under federal law. The majority opinion held that he could not because Congress had not specifically provided for such a conviction and thus did not have jurisdiction over him. In his dissenting opinion, Justice Field argued that Congress did indeed have authority to punish crimes committed by non-citizens within its borders regardless of when they arrived or from where they came. He reasoned that this power was necessary for national security and public order, as well as being consistent with international law principles which allowed nations to exercise criminal jurisdiction over foreigners on their soil even if those foreigners were citizens of another nation. Furthermore, he noted that allowing foreign nationals to commit serious crimes without consequence would undermine respect for U.S laws among both citizens and non-citizens alike