Justice Frankfurter, joined by Justices Burton, Clark, and Harlan, would have upheld the statute. He first rejected Trop’s proposed narrowing constructions: § 401(g) was not limited to desertion to the enemy, and the statute did not require a dishonorable discharge attributable exclusively to desertion rather than to a group of related military convictions.
In his view, Congress’s war powers include broad authority to raise, maintain, and discipline armed forces during wartime. Congress could rationally conclude that desertion gravely threatens military morale and fighting effectiveness, and that loss of citizenship was an appropriate consequence for refusing what Congress could regard as the ultimate duty of citizenship: serving in the Nation’s defense.
Justice Frankfurter rejected the characterization of denationalization as criminal punishment. Congress had enacted § 401(g) as part of a nationality scheme tied to its authority to regulate military conduct, and loss of citizenship could be treated as a collateral consequence of a valid conviction rather than as a penal sanction subject to the Eighth Amendment.
Even if denationalization were punishment, the dissent concluded that it was neither disproportionate nor cruel and unusual for wartime desertion, an offense historically punishable by death. Although the consequences of losing citizenship could be severe, a denationalized person in the United States would retain substantial constitutional protections as an alien and would not become the equivalent of an outlaw.
Finally, Justice Frankfurter warned that invalidating an Act of Congress requires judicial restraint. The Court’s task was to decide whether Congress had clearly exceeded a constitutional limit, not whether denationalization was wise, humane, or sound policy. In his view, the Court improperly substituted its judgment for Congress’s reasonable judgment under the war power.