A Senate Republican un-endorses the party's apparent nominee following his racial remarks about a judge who is involved in the Trump University trial.

FOX's Steve Taylor reports from Washington:

Senator Mark Kirk of Illinois had said he would back Donald Trump, but now Kirk has formally withdrawn that endorsement. Kirk says, "I cannot and will not support my party's nominee for President."

On a day when party leaders were criticizing Trump's negative comments about the judge he faces in the Trump University trial, Senator Kirk says "Trump has not demonstrated the temperament necessary" to be President.

Kirk is in a tough re-election fight in Illinois, where his Democratic opponent Tammy Duckworth, is trying to tie Mark Kirk to Donald Trump.

In Washington, Steve Taylor, FOX News.