Photo: Sara D. Davis/Getty Images

When Donald Trump realized that questioning the legitimacy of the first black president was no longer in his interest, he was faced with a challenge: How to make this change of political calculation look like a change of heart?

If the mogul had only declared victory once he had forced Barack Obama to present his papers — as though the commoner-in-chief were a resident of apartheid South Africa and not president of the United States — everything would have been so easy.

But Trump knew there was still skin on the bones of this “birther” thing. And he spent another five years gnawing at it, periodically expressing his doubts about the authenticity of the birth certificate Obama had displayed.

So, when Trump declared that the president had been born in this country, at the end of an informercial for his new hotel last Friday, he restricted his remarks to three short sentences.

“Hillary Clinton in her campaign of 2008 started the ‘birther’ controversy. I finished it,” Trump announced. “President Barack Obama was born in the United States, period.”

Even if he hadn’t replaced one outrageous lie with another, this statement would have left reporters wanting: Where was the mea culpa? The noble lie about how he had realized the error of his ways, and not merely the inconvenience of his past? The tearful confession about how he lost his mind to a conspiracy theory — but would now be donating $1 million to Tinfoil-Hat-Wearers Anonymous — which had played such a vital role in his recovery?

On Wednesday, the “why now” questioned finally caught up with Trump. Asked what changed his mind about Obama’s origins, in an interview with Ohio’s Fox 28, the Republican nominee replied: “Well, I just wanted to get on with, I wanted to get on with the campaign. A lot of people were asking me questions.”

Points for honesty; demerits for suggesting that there’s still no substantive reason to believe the sitting president is truly an American.

The least reporters can do in the wake of this statement is refuse to give the mogul what he wants. If Trump surrogate sheriff Joe Arpaio is still asking questions about Obama’s birthplace, the campaign press should follow suit.