The Human Rights Campaign on Saturday announced that it had revoked its endorsement of Republican Mark Kirk, after the Illinois senator attacked his opponent's mixed racial heritage during a debate.

It is the first time the influential human rights organization has withdrawn support from a candidate in its 36 years of operation.



When Rep. Tammy Duckworth — whose mother is Thai and whose father is American and served in the US Army — called herself a “daughter of the American Revolution,” Kirk made an inaccurate comment about her mixed heritage.

“I had forgotten that your parents came all the way from Thailand to serve George Washington,” he said during the debate.

Kirk did not immediately offer an apology for his comment, but tweeted one on Friday.