Immigration · Primary-source case analysis

Costello: A Conviction While Naturalized Did Not Trigger the Statute for an Alien Convicted After Entry

By Aneeta Mishra and Timothy Chan

Published May 16, 2026 · Updated October 18, 2026

Decision: Costello v. INS, 376 U.S. 120 (1964).

Costello v. Immigration and Naturalization Service examined whether later denaturalization retroactively satisfied the status language of a deportation statute tied to criminal convictions.

Status at conviction mattered

Costello became a naturalized citizen in 1925, was convicted in 1954 and lost his citizenship in 1959. The government argued that the denaturalization order’s statutory effective date reached back to 1925, making him an alien at conviction as a matter of law. Costello, 376 U.S. at 121, 128–129. The issue was not whether denaturalization was valid; it was how far its effect extended into another statute.

Later denaturalization did not rewrite that historical fact

The Court accepted that Congress had adopted relation back for denaturalization itself. But it found no language or specific legislative history extending that fiction to the general deportation ground at issue. Earlier cases using relation back for derivative citizenship did not establish its reach here. Costello, 376 U.S. at 129–130. The decision therefore does not say that revocation has no retroactive effects for any purpose.

The statutory wording controlled

The government acknowledged that relation back could not be applied mechanically. One reason mattered in practice: Treating Costello as an alien at his earlier sentencing would not restore the protective sentencing procedure he had been unable to use while a citizen. It could leave him worse off than if he had never naturalized. The same theory would also reach naturalization later invalidated for a technical defect, not just fraud. Costello, 376 U.S. at 130–132.

The deportation order could not stand on that ground

The Court reversed on statutory grounds. It did not hold that Congress lacked constitutional power to specify a different result. The dissent argued that the current alien status and earlier convictions already satisfied the statute; the majority rejected that reading. Costello, 376 U.S. at 132–135 (White, J., dissenting). Do not turn this decision into a blanket promise that denaturalization leaves earlier conduct irrelevant.

Key takeaways

• Track immigration status at entry, conduct, conviction, and adjudication separately.
• Use the exact status language of the charged removal ground.
• Do not assume later events operate retroactively.
• Evaluate alternative grounds independently.