(CNN) Just as Donald Trump gained on Hillary Clinton this week, he returned to his old ways of self-sabotage.

As the "birther" controversy swelled around him, he stood before a national television audience seemingly poised to address the issue that launched his political career -- and then he spent 30 minutes delivering an infomercial about his new hotel. As the event was about to wrap, he tossed out a near-throwaway line: "President Barack Obama was born in the United States. Period."

Whatever game Trump was playing with the issue in the past few days, it backfired.

Trump never had much of a chance with African-American voters. They are traditionally among the most loyal Democratic supporters, and many black voters viewed Trump's championing of the birther movement since 2011 as a racist effort to delegitimize the first African-American president.

But for weeks, the real estate has been trying to appeal to African-Americans with visits to Detroit and Flint, Michigan, as well as speeches accusing the Obama administration of leaving too many black Americans behind in poverty or without good-paying jobs.

Those entreaties, in many cases, seemed to backfire. This week, he insulted a black pastor from Flint as a "nervous mess" after she interrupted his speech to ask him not to deliver political attacks in her church.

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And given the animosity toward Trump among African-Americans, the campaign's strategy seemed more keyed to assuaging concerns among some Republican voters and independents that Trump's rhetoric is racist.

The strategy of softening Trump's image among reluctant Republicans and independents showed some signs that it was working. This week, Trump's poll numbers inched up in battleground states, and the Clinton-Trump race nationally was deadlocked once again.

But Trump's curious moves Thursday night and Friday were a reminder of how quickly his effort can go off the rails.

Black congressional leaders, along with Clinton's campaign, pilloried Trump's brief statement on Obama's birthplace -- which was not an apology, an explanation or even an admission that he was the loudest promoter of the birther movement.

At a press conference, member of the Congressional Black Caucus urged voters to register and get out and vote this November.

"We are used to dog whistles, but the thing we are not used to are the howls of wolves. These are howls, not whistles," said Rep. James Clyburn of South Carolina.

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That disdain for Trump could well become an asset to Clinton's campaign, particularly among younger African-American voters who aren't excited about her candidacy and might have otherwise stayed home.

Moreover, Trump was widely derided Friday for his false claim that "Hillary Clinton and her campaign of 2008 started the birther controversy" and that "I finished it."

Clinton's campaign manager, Robby Mook, called Trump's actions "disgraceful."

"After five years of pushing a racist conspiracy theory into the mainstream, it was appalling to watch Trump appoint himself the judge of whether the President of the United States is American," Mook said in a statement. "This sickening display shows more than ever why Donald Trump is totally unfit be president."

While some 2008 supporters of Clinton used Internet blogs to raise questions about Obama's birthplace, the Clinton campaign never promoted the conspiracy theories. The Clinton campaign, in fact, severed ties with a volunteer coordinator in Iowa who forwarded an email promoting the birther conspiracy, according to Clinton's 2008 campaign manager, Patti Solis Doyle.

Clinton's campaign clearly intends to use Trump's puzzling revival of the birther controversy as its latest illustration of why he is not fit to be commander in chief. Her campaign argued Friday that Trump's embrace of the birther movement "turned Trump from an ordinary reality TV star into a political figure."

"Trump has spent years peddling a racist conspiracy aimed at undermining the first African-American president," Clinton's campaign tweeted. "He can't just take it back."

While this issue is sure to rage on -- and come up in first the debate between Clinton and Trump -- the current commander in chief apparently is ready to turn to other topics.

"I think when the President released the long form version of his birth certificate in this room five years ago he was hoping that people would move on," White House Press Secretary Josh Earnest said in the White House briefing room.

"With regard to an apology" from Trump, Earnest said, "I don't think the President much cares."