Perez v. Brownell

The Court voted 5-4 to deny Perez's claim. According to Justice Frankfurter's decision, the first key point was Congress's authority to pass the Nationality Act. Frankfurter said the Constitution does not specifically grant Congress the power to regulate foreign affairs, but through its legislative duties Congress can "deal affirmatively with foreign nations" or "reduce to a minimum the frictions that are unavoidable in a world of sovereigns . . . " Passing the Nationality Act was a valid use of congressional power.

Next, Frankfurter examined whether preventing Americans from voting in foreign elections was a legitimate use of that power. (In its decision, the Court only focused on Perez's voting in Mexico, not his attempt to avoid military service). It was, since:

. . . the activities of the citizens of one nation when in another country can easily cause serious embarrassments to the government of their own country as well as to their fellow citizens. We cannot deny to Congress the reasonable belief that these difficulties might well become acute, to the point of jeopardizing the successful conduct of international relations, when the citizen of one country chooses to participate in the political or governmental affairs of another country. The citizen may by his action unwittingly promote or encourage a course of conduct contrary to the interests of his own government.

Lastly, the Court found that the punishment of expatriation fit the act committed, even if by voting in a foreign land a citizen did not intend to give up his citizenship. "The termination of citizenship terminates the problem."