President Obama this weekend issued perhaps his most urgent appeal yet for Hillary Clinton, telling African-Americans that he would “consider it a personal insult” if they don’t turn out to vote for the Democratic nominee in November.

“I will consider it a personal insult, an insult to my legacy, if this community lets down its guard and fails to activate itself in this election,” Obama said Saturday in his address to the Congressional Black Caucus Foundation in Washington. “You want to give me a good sendoff? Go vote!”

The president also fired back at GOP nominee Donald Trump, who on Friday for the first time reversed his stance on the controversial “birther” movement. Trump for years had been one of the conspiracy theory’s most forceful promoters, raising questions about whether Obama was born in Kenya and even demanding the public release of the president’s birth certificate.

On Friday, Trump told reporters, “President Barack Obama was born in the United States, period.”

See also: Why Trump’s Latest Speech Will Do Nothing to End the Birther Controversy

 

“I don’t know about you guys, but I am so relieved that the whole ‘birther’ thing is over,” Obama joked on Saturday. “In other breaking news, the world is round, not flat.”

But the president didn’t mince words when it came to uniting African-Americans behind his former secretary of state. Taking Trump to task for asking black voters “what the hell” they have to lose by voting for him, Obama said, “My name may not be on the ballot, but our progress is on the ballot.”

Republicans have long accused the Democrats of taking the black vote for granted each election season.

See also: Read Michelle Obama’s First Campaign Trail Speech for Hillary Clinton

Back in 2008, many older black women had considered the Democratic primaries between Clinton and Obama “an agonizing choice between supporting a candidate who could become the first female president, or the one who might become the first black one,” according to The New York Times.

But this year’s decision is turning out to be least slightly more nuanced. Though Clinton still enjoys a massive lead—83% in one Times/CBS News poll—over Trump with African-Americans, both she and her husband have been forced to deal with fiery confrontations from younger voters out on the trail this year, including accusations over Bill Clinton’s 1994 crime bill that many blame for disproportionately affecting African-Americans, and questions on the role of Black Lives Matter in today’s hyper-charged political climate.

See also: Who Is Funding Black Lives Matter?

Clinton’s campaign is planning to leverage both the president’s and the first lady’s popularity “as much as possible in the coming weeks,” especially in Florida, Ohio, and North Carolina, according to the Times.

“You may have heard Hillary’s opponent in this election say that there’s never been a worse time in America to be a black person,” Obama said on Saturday. “He missed that whole civics lesson about slavery and Jim Crow, but we’ve got a museum for him to visit. So he can tune in. We will educate him.”