"I cannot and will not support my party's nominee for President regardless of the political impact on my candidacy,” said Mark Kirk. | Getty Kirk: 'I cannot and will not support my party's nominee'

Illinois Sen. Mark Kirk, the most endangered Senate Republican up for reelection this fall, said Tuesday that he will not back Donald Trump for president after a long line of controversial comments from the presumptive GOP nominee.

“As the presidential campaign progressed, I was hoping the rhetoric would tone down and reflect a campaign that was inclusive, thoughtful and principled,” Kirk said in a statement released Tuesday by his campaign. “While I oppose the Democratic nominee, Donald Trump's latest statements, in context with past attacks on Hispanics, women and the disabled like me, make it certain that I cannot and will not support my party's nominee for President regardless of the political impact on my candidacy or the Republican Party.”


Trump has triggered an uproar in the GOP with his latest attack on a federal judge’s ethnicity, arguing that he cannot properly oversee the legal case into Trump University because of his Mexican heritage.

"I have spent my life building bridges and tearing down barriers — not building walls,” Kirk said. “That's why I find Donald Trump's belief that an American-born judge of Mexican descent is incapable of fairly presiding over his case is not only dead wrong, it is un-American.”

Kirk had indicated before Trump became the presumptive nominee that he would support him as the standard bearer. But on Tuesday, Kirk said he has concluded that the businessman “has not demonstrated the temperament necessary to assume the greatest office in the world.”

Kirk's statement read in full:

"I have spent my life building bridges and tearing down barriers — not building walls. That's why I find Donald Trump's belief that an American-born judge of Mexican descent is incapable of fairly presiding over his case is not only dead wrong, it is un-American.

"As the Presidential campaign progressed, I was hoping the rhetoric would tone down and reflect a campaign that was inclusive, thoughtful and principled. While I oppose the Democratic nominee, Donald Trump's latest statements, in context with past attacks on Hispanics, women and the disabled like me, make it certain that I cannot and will not support my party's nominee for President regardless of the political impact on my candidacy or the Republican Party.

"It is absolutely essential that we are guided by a commander-in-chief with a responsible and proper temperament, discretion and judgment. Our President must be fit to command the most powerful military the world has ever seen, including an arsenal of thousands of nuclear weapons. After much consideration, I have concluded that Donald Trump has not demonstrated the temperament necessary to assume the greatest office in the world.”

