United States v. Allen is a United States Supreme Court case that was decided in 1887. The case involved a dispute between the United States and Allen, a former employee of the United States Post Office. Allen had been convicted of embezzlement and was sentenced to two years in prison. The United States appealed the conviction, arguing that the trial court had erred in its instructions to the jury. The Supreme Court held that the trial court had erred in its instructions to the jury. The Court found that the instructions given to the jury were not sufficient to support a conviction for embezzlement. The Court noted that the instructions did not adequately explain the elements of the crime of embezzlement, and that the jury was not properly instructed on the law of embezzlement. The Court reversed the conviction and remanded the case for a new trial. The Court held that the jury should have been properly instructed on the elements of the crime of embezzlement, and that the instructions given to the jury were not sufficient to support a conviction. The Court also noted that the jury should have been instructed on the law of embezzlement in order to properly evaluate the evidence presented at trial.

In United States v. Allen, the Supreme Court was asked to decide whether a defendant could be convicted of an offense under two different statutes for the same act. The majority opinion held that it was permissible in this case because each statute required proof of different elements and thus constituted separate offenses. Justice Field dissented from this decision, arguing that allowing multiple convictions for one act would lead to double jeopardy and violate principles of fairness. He argued that if Congress intended such a result they should have explicitly stated so in their legislation rather than leaving it up to judicial interpretation. Furthermore, he noted that permitting multiple convictions based on similar facts would create confusion among jurors as well as encourage prosecutors to charge defendants with numerous counts even when only one crime had been committed in order to increase chances of conviction or leverage plea bargains out of defendants who may not otherwise plead guilty due to fear of harsher sentences associated with more charges.