Donald J. Trump has a birther fetish.

When he was leading the polls by a country mile, he saw no issue with the background of fellow Republican presidential candidate Ted Cruz. The Canadian-born U.S. senator from Texas has qualified fully to run for president, Trump said. “He’s in fine shape,” he said of his GOP rival.

But wait! Circumstances have changed. Cruz is neck-and-neck with Trump. He’s overtaken him in Iowa, according to some surveys.

Now-w-w-w there’s a problem, Trump said.

“People” have called Cruz’s qualifications into question, Trump said. It could present a problem for the Republicans if Cruz is their nominee, Trump added.

So, which is it, Donald. Is Cruz eligible to run and serve as president or isn’t he?

Trump has raised this birther crap before. The other time involved President Barack Obama, who was born in Hawaii — one of the 50 United States of America. Trump, though, didn’t believe it; for that matter, I’m not sure he believes it yet.

The Constitution stipulates that only “natural-born” citizens can run for the office and serve if elected. Yes, Cruz was born in Canada. But he earned U.S. citizenship the moment he came into this world because — get ready for it — his mother is an American. Daddy Cruz is Cuban, but that doesn’t matter. Cruz is eligible to run for the highest office.

Don’t take my word for it. Others who are a whole lot smarter than I am have said the same thing. Constitutional lawyers have affirmed Cruz’s eligibility.

So, what’s Trump’s beef?

Oh yeah. It’s those polls.

I love, too, how Trump keeps shoving this issue off to “people” who’ve said such things. Well, Trump has said it, too.

It kind of reminds me of the time Sen. Walter Mondale — the 1976 Democratic vice-presidential nominee — came to Portland, Ore., to campaign for the White House. He held a press event in which a reporter asked him if Watergate was going to be an issue in the presidential campaign.

Mondale, grinning from ear to ear, said, “I am not going to make President Ford’s pardon of Richard Nixon an issue in this campaign.”

I guess Mondale was going to let “people” talk about it.