Boris Johnson, who led the campaign for Britain to leave the European Union, speaks in London on June 30. He was born in New York and is believed to hold dual citizenship. (Toby Melville/Reuters)

Boris Johnson stunned the world this week when he withdrew from the campaign to become Britain’s next prime minister. The shaggy-haired member of Parliament was one of the driving forces behind the country’s decision to abandon the European Union and had been a prime candidate to take the political reins from outgoing Prime Minister David Cameron.

His fall from grace is the latest chapter in a Shakespearean political drama that has left many pundits wondering what Johnson’s next act could possibly be.

One thought: America.

Johnson was born in New York, and that makes him a U.S. citizen. Yes, you read that right. The man behind the Brexit, or British exit from the E.U., the referendum that is changing the course of European history and threatening to tear apart the United Kingdom, is actually an American.

Johnson has called this inconvenient fact an “accident of birth.” Technically, he holds dual citizenship in the United States and Britain. Of course, he identifies as British and has the accent to prove it, but local media reported that he renewed his American passport as recently as 2012.

More than a year ago, Johnson announced that he intended to renounce his citizenship. A Washington Post search of public records found no indication that he has done so. The Treasury Department and the Internal Revenue Service publish the names of Americans who have relinquished their passports every quarter. Johnson has not been on any of the lists published between the time of his announcement and May, the most recent release. (His full name is Alexander Boris de Pfeffel Johnson.)

Johnson also reportedly said he would contact the U.S. Embassy in Britain to renounce his citizenship. A spokeswoman for the embassy said she could not confirm whether he had done so, citing privacy concerns. A request to Johnson’s office for comment has not been returned.

Being American could have put Johnson in an awkward spot had he put himself forth for prime minister. Andrew Blick, a political history professor at King’s College in London, said there are few formal requirements for the position but that no premier has held a dual citizenship.

Then there is the matter of taxation. America is one of the only countries in the world that requires its citizens to pay taxes even when they’re living abroad. After Johnson sold a home in north London, the BBC reported that he paid capital gains tax last year at a rate he called “absolutely outrageous.”

The consequences of not paying U.S. taxes could be even worse. Under new regulations, penalties range from $10,000 for a forgotten form to $100,000 or more for intentional obfuscation.

But Johnson’s U.S. papers could come in handy right about now. Back in 2012, he broached the possibility — jokingly, we assume — that he could technically run for president during an interview with former late-night talk show host David Letterman. The Constitution requires only that the person sitting in the Oval Office be 35 years old, a resident for at least 14 years and a “natural born citizen.”

Indeed, Johnson's claim to the last criteria is stronger than that of former GOP presidential candidate Ted Cruz, whose mother is American but was born in Canada. If Johnson spent a little time on the other side of the pond, he would be on solid legal footing.

That leaves us with this conundrum: Which is more likely — a British American in the White House or an American Brit in 10 Downing Street?