IT SAYS SOMETHING embarrassing — actually, make that disturbing — about the state of American politics that the president of the United States took to the White House briefing room Wednesday to prove that he had, in fact, been born in the United States. The White House’s move to unseal, and release, Barack Obama’s birth certificate came after polls indicated a growing number of Americans doubting that basic fact. A USA Today/Gallup Poll released Monday showed that just 38 percent believe that Mr. Obama was “definitely” born in the United States, with 18 percent saying he “probably” was.

As the long-form birth certificate disgorged by Hawaii authorities and released by the White House demonstrates once and for all, this is complete nonsense. The “birther” delusion would be laughable if it were not so widespread and if it did not carry with it the unmistakable whiff of racism. We doubt that the questions about Mr. Obama’s birthplace would have taken off if his father had been from Canada rather than Kenya.

At the same time, there was a certain amount of play-acting in Mr. Obama’s assertions of injury. If anything, the decision by developer and potential Republican presidential candidate Donald Trump to seize on the “birther” issue played into Democrats’ hands: It allowed Mr. Obama to position himself as the sane grown-up to Mr. Trump’s “carnival barker.”

The president asserted Wednesday that he would not normally dignify these claims with a response but that the birther debate was drowning out the more important discussion about the budget. “The dominant news story wasn’t about these huge, monumental choices that we’re going to have to make,” the president said. “It was about my birth certificate. And that was true on most of the news outlets that were represented here.”

Not by our count. On broadcast and cable networks, far more stories overall have mentioned the proposal by House Budget Committee Chairman Paul Ryan (R-Wis.) than the birther debate in the past several weeks. The New York Times ran nine articles and columns touching on the “birther” controversy, mostly to debunk or ridicule it. The Post had about a dozen doing much the same. By contrast, Mr. Ryan’s budget plan drew 64 mentions in the Times and 96 in The Post since April 4, the day it was released.

Nonetheless, Mr. Obama is correct that the country has more important matters to discuss than the presidential birth certificate. Mr. Trump was busy crowing Wednesday that he had done the country a service by prodding the president to release the document. Now Mr. Trump appears to be ready to pivot to the equally bogus issue of the president’s grades in college and law school. Our advice to Mr. Trump: Cease and desist. As Mr. Obama said Wednesday, “We do not have time for this kind of silliness.”