Nikki Haley
"The Late Show" host said the former president should be worried by what happened this week.
The backing signals persistent discontent among party voters with the former president.
Trump is still losing significant votes in some GOP primaries despite being the party's presumptive nominee.
The ad features Donald Trump insulting Haley and saying he doesn't need her supporters' votes.
WHAT'S HAPPENING
Adam Kinzinger taunted "Chief Whiney" over results in Tuesday's primaries.
"He always gives into his worst instincts," Alyssa Farah Griffin said on CNN.
"You know what that means," joked the "Tonight Show" host.
The Republican Accountability PAC put the former president on blast for his comments about other Republicans.
The failed Arizona gubernatorial candidate made a post on X, formerly Twitter, mocking Haley's birth name.
"There is a place for them in my campaign," the president said of voters who'd backed Haley, who just suspended her campaign.