Why the U.S. Quietly Tolerates Dual Citizenship
Picture the moment right after a naturalization ceremony. A woman from Toronto walks out of a Brooklyn courthouse holding a small American flag, a certificate of naturalization, and — tucked in her bag — a perfectly valid Canadian passport. Ninety seconds earlier she swore to absolutely and entirely renounce and abjure all allegiance to any foreign state. Now she is legally Canadian and legally American at the same time, and nobody is coming for the second passport.
That gap between the oath’s thunder and the paperwork’s calm is exactly what people mean when they search for why the US allows dual citizenship. The honest answer: America never wrote a statute saying dual citizenship is fine. It wrote laws saying the opposite, spent fifty years enforcing them, and then backed off — for reasons that mix constitutional limits, diplomatic self-interest, and plain arithmetic.
- No U.S. statute grants dual citizenship — and none bans it. The State Department’s own manual discusses ‘dual nationality’ and notes U.S. law doesn’t force you to pick one name or the other.
- Afroyim v. Rusk (1967) held that Congress cannot strip citizenship without your consent, which makes unilateral crackdowns nearly impossible.
- Naturalizing in the U.S. doesn’t erase your birth citizenship. The other country’s law decides that, not Washington’s.
- Dual status comes with real strings: U.S. taxes wherever you live, a U.S. passport required to enter the U.S., and possible friction with security clearances.
The Oath Sounds Absolute — The Law Isn’t
Listen to the wording new citizens repeat: they renounce all allegiance to any foreign prince, potentate, state, or sovereignty. It lands like a clean break. It isn’t one.
Allegiance and nationality are two different things, and only one of them is Washington’s to give or take. Taking the U.S. oath of naturalization does not, under U.S. law, automatically cancel your other citizenship. The State Department’s Foreign Affairs Manual openly addresses dual nationality and says American law doesn’t require a person to choose between their two nationalities. That isn’t a ringing endorsement. It’s an acknowledgment that the choice isn’t America’s to force.
So the real question isn’t why the U.S. allows dual citizenship. It’s why the U.S. stopped trying to crush it. Three forces did the work: the Constitution, the courts, and the discovery that enforcement was hopeless.
The 1967 Ruling That Tied Congress’s Hands
For the first half of the twentieth century, Congress treated dual status as a defect to be scrubbed out. The Expatriation Act of 1907 stripped citizenship from American women who married foreign nationals. A web of treaties let each country deport the other’s naturalized citizens who returned home too soon. In the 1950s, the Supreme Court went along — Perez v. Brownell upheld the loss of citizenship for a man who had voted in a Mexican election.
Then came Beys Afroyim, a Polish-born painter who naturalized in the United States in 1926, later moved to Israel, and voted in an Israeli election in 1951. The government declared he had surrendered his American citizenship under a Cold War statute that punished voting abroad. In 1967, the Supreme Court disagreed 5–4.
Afroyim v. Rusk held that the Citizenship Clause of the Fourteenth Amendment gives Congress no power to take away citizenship without the person’s consent. Thirteen years later, Vance v. Terrazas added the second brick: expatriation requires a voluntary act performed with the specific intent to give up U.S. citizenship, and the government carries the burden of proving that intent. It rarely can.
Read those two cases together and the whole puzzle snaps into place. The United States cannot revoke your citizenship because you hold another passport. You have to walk away on purpose. Most dual nationals never do — and most other countries won’t unilaterally cancel their side either. Dual status simply persists, legal and unremarkable.
What Dual Status Looks Like When It Meets Real Life
| Situation | What U.S. law actually says |
|---|---|
| You naturalize in the U.S. and keep your birth citizenship | Fine. The oath renounces allegiance; it doesn’t cancel the other country’s nationality. Their rules decide whether you keep it. |
| You’re born abroad with one U.S. parent and a foreign passport | Fine. You can hold both from birth, and the U.S. doesn’t make you choose at eighteen. |
| You naturalize in another country as an adult | Technically on the list of potentially expatriating acts, but since the 1990s the State Department presumes you intended to keep U.S. citizenship unless you clearly said otherwise. |
| You run for office or take a government job in another country | Can trigger loss of citizenship, but only if the government proves intent to relinquish. A second passport alone won’t do it. |
| You fly home to the United States | You must enter and leave on your U.S. passport, even when the other one is more convenient. |
| You want out for good | Renunciation happens in person before a U.S. consular officer abroad, is irrevocable, and carries a fee that has run into the thousands of dollars. |