A Democratic super-PAC released an ad on Wednesday attacking Sen. Mark KirkMark Steven KirkDuckworth announces reelection bid Brave new world: Why we need a Senate Human Rights Commission  Senate majority battle snags Biden Cabinet hopefuls MORE (R-Ill.) for revoking his support of presumptive Republican presidential nominee Donald TrumpDonald TrumpIran claims U.S. to lift all oil sanctions but State Department says 'nothing is agreed' Ivanka Trump, Kushner distance themselves from Trump claims on election: CNN Overnight Defense: Joint Chiefs chairman clashes with GOP on critical race theory | House bill introduced to overhaul military justice system as sexual assault reform builds momentum MORE.

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The ad, produced by American Bridge 21st Century, shows a series of clips of Trump making divisive comments throughout the primary, before he secured the nomination. It follows up with a clip of Kirk saying he’d support Trump if he were the party’s nominee.

Kirk withdrew that support on Tuesday.

“Republicans knew they were endorsing,” on-screen text reads as the ad ends.

Kirk, who is in a difficult Senate reelection race against Rep. Tammy Duckworth (D-Ill.), responded to the ad by tying Duckworth to Trump.

"Ironically, Trump and Duckworth have much more in common than people think," Kirk's campaign manager, Kevin Artl, said in a statement. "Both supported corrupt former Illinois Governor Rod Blagojevich and both are headed to trial."

Duckworth has been accused by two former employees of the state’s Department of Veterans Affairs of retaliating against them while she headed the agency. A trial date has been set for Aug. 15.