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Obama’s Senate seat is back in Democratic hands.

Mark Kirk has had a target on his back ever since he clinched his Senate seat during the Tea Party wave of 2010. Running in a blue state, he has tried to distance himself from the polarizing Republican nominee, Donald Trump, by promising to pencil in former CIA Director David Petraeus.

After a hotly contested Democratic primary, Tammy Duckworth—an Illinois congresswoman who lost both her legs serving as a helicopter pilot in the Iraq War—emerged as a formidable opponent. But it was only when Kirk openly questioned her heritage during a staggering moment in their October 27 debate that the Republican incumbent looked like he would definitely lose.

“My family has served this nation in uniform going back to the Revolution,” Duckworth said. “I am a daughter of the American Revolution. ... Families like mine are the ones that bleed first.”

“I’d forgotten that your parents came all the way from Thailand to serve George Washington,” Kirk replied.

And with that, all his efforts to distance himself from the xenophobic Republican nominee went out the window. He lost endorsements from key groups like the Human Rights Organization. Duckworth sailed to victory tonight, flipping the Democrats’ first state and bringing them one step closer to taking back the Senate.

Correction: A previous version of this post incorrectly stated that Kirk promised to vote for retired General Stanley McChrystal.