U.S. Sen. Mark Kirk, R-Ill., who broke ranks earlier this month and announced he would not support Donald Trump as his own party’s presidential nominee, became the first GOP incumbent to run an anti-Trump ad Friday.

Kirk, who is considered one the most endangered Republican incumbents, dropped a 30-second ad titled “Even More,” which declares Trump “is not fit to be commander in chief.”

The ad portrays Kirk, 56, who suffered a devasting stroke in 2012 that kept him off the job for nearly a year, as the un-Republican, CBS News reported, touting his bipartisan support for some Democratic positions, including calling for a vote on President Barack Obama’s U.S. Supreme Court nominee, Judge Merrick Garland. Senate GOP leaders have refused to give the nomination an airing.

“Mark was the first Republican to support a vote on President Obama’s Supreme Court nominee,” the ad says. “He’s a leader on protecting a woman’s right to choose.”

The junior senator from Illinois was first elected to Obama's former seat in 2010 and is among those being targeted by the Democrats in the fall. He faces Rep. Tammy Duckworth, D-Ill., a disabled Iraq war veteran who forced Kirk to come out against Trump by calling the suburban Chicago Republican “complicit” in Trump’s campaign of “hate and division.”

The Chicago Tribune reported that Kirk bought $230,000 in broadcast time for a weeklong ad run in Chicago and $35,520 in cable TV time to promote himself as independent of his party.

“After facing death, Kirk returned even more committed to serve Illinois,” a female narrator says, alluding to the stroke.

The Duckworth campaign issued a statement, highlighting Kirk’s past misstatements about his military record, which were an issue in 2010, and accusing him of trying to portray “himself as a liberal Democrat in Chicago while apparently hoping no one else across the state notices.”

mark kirk U.S. Sen. Mark Kirk (right), R-Ill., climbs the Capitol stairs upon his return to the Senate after a stroke, Jan. 3, 2013. Photo: Jewel Samad/AFP/Getty Images

Kirk last year incurred the wrath of women and African-American voters when he described unmarried Sen. Lindsey Graham, R-S.C., as a “bro with no ho,” adding, “That’s what we’d say on the South Side,” a reference to a mostly black section of Chicago. In 2014, he referred to Senate staffers who prepared a report on harsh CIA interrogation techniques as “little zombies,” reaching up from their “political graves.” In 2013, he was criticized for calling for the mass arrest of what he called 18,000 Gangster Disciples street gang members and last year said in an interview with the Peoria Journal Star that people drive faster through black neighborhoods.