But the manner in which Trump announced his change of heart could backfire on him and end up boosting Clinton.

Rather than show contrition or explain his reasoning, Trump, during an event to promote the opening of his new hotel in Washington, D.C., delivered a terse statement accusing Clinton of fomenting the “birther” conspiracy and taking credit for putting it to rest.

Democrats were incensed, and Clinton now has an opportunity to use that anger to energize her base.

That matters because Clinton’s drop in the polls corresponds directly to a significant diminishing of enthusiasm among registered Democrats. Recent surveys show them less likely to vote than just a few weeks ago.

Reminding Democrats of Trump’s role in fanning “birtherism” could motivate them to re-engage with Clinton, while also hurting the Republican nominee’s ability to appeal to suburban swing voters.

“If Donald Trump thought today would whitewash his well documented perpetuation of a racist conspiracy theory he was mistaken,” Rodell Mollineau, a Democratic strategist, told the Washington Examiner. “I doubt he changed the mind of a single African-American voter and he reminded a whole swath of moderates and independents that he is prone to despicable actions.”

Clinton since Labor Day has watched her months-long lead over Trump disintegrate. She was still clinging on Saturday to a small lead in the RealClearPolitics average of recent national polls. But the latest polling from the battleground states show her tied or losing to Trump.

Fresh attention on the scandals surrounding Clinton have taken a toll, as did her absence from the trail for most of last week due to pneumonia. There’s also the fact that Trump has become a more disciplined campaigner who has done a better job of generating negative controversy.

Some Republicans are predicting that the renewed focus on Trump’s role in the Obama “birther” conspiracy is unlikely to derail his momentum, speculating that he could even emerge from the events of the last few days in a stronger position.

“I think in the rest of the nation no one cares about that issue anymore. But he stole the news cycle again,” said David Carney, a Republican strategist in New Hampshire.

However, public opinion polls have shown voters are wary of Trump partly because of the high profile, racially charged controversies surrounding his campaign, leading strategists in both parties to view the renewed spotlight on the conspiracy as a political opening for Clinton to reclaim the lead.

The Democratic machine moved quickly to capitalize.

Ahead of Trump’s retraction, announced in a two-sentence statement around noon on Friday, Clinton delivered a speech to a group of African-American women in Washington, D.C., arguing that Trump couldn’t “erase” his history as the primary instigator of birtherism.

After Trump revealed he’d changed his mind, Democrats in Congress who are African-American held a lengthy press conference denouncing Trump as a racist and a bigot.

Meanwhile, Priorities USA, a super political action committee spending tens of millions of dollars to elect Clinton, launched a $400,000 digital advertising campaign with a similar message targeting African-American voters in Florida, North Carolina, three crucial swing states.

A key data point in Clinton’s recent decline in public opinion surveys was the drop in enthusiasm among Democratic voters, leading pollsters to conclude that fewer Democrats were likely to vote in November. This month pollsters tighened their focus to voters considered most likely to vote in November, as opposed to the broader universe of “registered voters,” among whom Clinton still tends to have an advantage.

“Right when he was starting to show some discipline — right when he was starting to gain some momentum and right when he was about to make this race a referendum on Hillary Clinton, Trump goes and finds a way to squander all of it with a self-inflicted wound,” a Republican strategist who has advised presidential candidates said on condition of anonymity.

Obama was born and raised in Hawaii. Yet in dark corners on the right, some cling to the notion that Obama, the nation’s first African-American president, was born in Kenya, the country of origin and citizenship of the president’s father.

The conspiracy was quitely peddled by a few Democrats during the 2008 Democratic presidential primary that pitted Obama and Clinton against each other. But contrary to Trump’s claims, neither Clinton nor her campaign ever pushed the matter; the 2008 Clinton campaign even fired a low-level volunteer who did after finding out what this individual was up to.

Obama later picked Clinton to serve as his first secretary of state, and he and his wife, first lady Michelle Obama, have campaigned vigorously for her this year.

In 2011, Trump used his fame to breathe life into what has always been considered a fringe conspiracy. Then running his real estate empire and hosting a reality television show on NBC, Trump toyed with running for president in 2012 and used the birther conspiracy to gain attention and support among GOP primary voters.

Obama eventually released his long-form birth certificate to quell any controversy. Trump responded by suggesting the document was a fake, and for the next five years — until Friday — pointedly refused, when periodically asked, to disavow the conspiracy.

Democrats, and some Republicans, don’t view this as a form of harmless showmanship used simply as a tool for Trump to boost his political fortunes among Republicans after years of supporting Democratic politicians and their liberal policies.

They see Trump’s promotion of birtherism as a sinister form of racism intended to delegitimize Obama because he is African-American. These strong feelings could give Obama’s voting coalition a reason to get behind Clinton in the numbers they did for the president in 2008 and 2012.

If they do, Clinton could be hard to beat.

“This just shows desperation on Trump’s part,” said Ed Espinoza, a Democratic operative based in Austin. “He led the charge on the birther thing and now he’s trying to put it on Clinton, but he’s too big of an idiot to realize people will see through it.”