Who says Donald Trump lacks subtlety? The way he’s raising “birther” questions about his chief rival for the nomination is worthy of Machiavelli.

“I’d hate to see something like that get in his way,” Trump said of the fact that Sen. Ted Cruz (R-Tex.) was born in Canada. Trump referred to the Constitution’s provision that “No Person except a natural born Citizen” — whatever that means — is eligible to be president.

“But a lot of people are talking about it,” Trump continued, in an interview with Post reporters, “and I know that even some states are looking at it very strongly, the fact that he was born in Canada and he has had a double passport.”

Cruz flatly denied ever having a Canadian passport, telling CNN that this was just one of those “silly sideshows” the media love to engage in. But there is no question that he was born in Calgary, Alberta, to an American mother and a Cuban father. And there is no question that he had Canadian citizenship — before renouncing it in preparation for his presidential run.

Ah, what goes around comes around. For years, the Republican Party had nothing but patronizing nods and winks for the unhinged birthers — Trump included — who claimed, despite definitive proof to the contrary, that President Obama was born in some other country. Now, as party leaders desperately look for a way to deny Trump the nomination, the candidate with the best chance of doing so happens to have been born, without any doubt, in some other country.

Donald Trump and Ted Cruz avoided going after each other on the debate stage or the campaign trail – until this week. The Fix's Chris Cillizza explains why the Trump-Cruz dynamic isn't going away any time soon. (Peter Stevenson/The Washington Post)

Trump still leads the national Republican polls by a mile, while Cruz has pulled ahead of the rest of the field and now stands alone in second place. In first-to-vote Iowa, however, Cruz has taken a narrow lead over the bombastic billionaire and is favored to win. Hence Trump’s sudden concern over the birthplace of a man who perhaps should be nicknamed Calgary Ted.

“Republicans are going to have to ask themselves the question: ‘Do we want a candidate who could be tied up in court for two years?’ That’d be a big problem,” Trump told The Post. “It’d be a very precarious one for Republicans because he’d be running and the courts may take a long time to make a decision.”

Most legal experts agree that Cruz is eligible to run; the fact that his mother was a U.S. citizen means he had citizenship from birth, which would appear to satisfy the “natural born” requirement. But the question of precisely what the Constitution means has never been fully explored by the courts.

The issue came up in 2008 because Sen. John McCain (R-Ariz.) the GOP nominee, was born in the Panama Canal Zone to parents who were U.S. citizens. The Senate went so far as to pass a nonbinding resolution “recognizing that John Sidney McCain, III, is a natural born citizen.”

You’d think McCain might be sympathetic to Cruz’s situation, but did I mention that what goes around comes around? Cruz has gone out of his way to alienate many of his Senate colleagues, and McCain has called him and his allies “wacko birds.” Perhaps that’s why McCain, when asked by a Phoenix television station to comment on Cruz’s eligibility, responded: “I think there is a question. I’m not a constitutional scholar on that, but I think it’s worth looking into.”

McCain noted that the Canal Zone was “a territory of the United States of America” when he was born. And there was a precedent, he argued, since 1964 Republican candidate Barry Goldwater was born in Arizona when it, too, was a U.S. territory.

Whereas Canada is a whole different country.

I confess that I find the whole flap absurd. Cruz should be deemed unsuitable for the presidency because of his wrongheaded ultra-right-wing views and his dangerous political ruthlessness, not because his American mother happened to be living in Canada when he was born.

But maybe Cruz will have to squirm a bit. A lawsuit has been filed in Vermont to keep him off the ballot there, and I wouldn’t be surprised if suits were filed in other states as well. Somehow I doubt he’ll get the same moral support from his fellow senators that McCain was given.

Has the party of Lincoln really come to this, Donald Trump or Ted Cruz? The two men still insist that they like each other, their campaign-long bromance not extinguished. I’m reminded of something Machiavelli didn’t say but should have: Keep your friends close and your enemies closer.

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