Donald Trump, left, listens as Michael Sexton introduces him at a news conference in New York where he announced the establishment of Trump University. (Bebeto Matthews/Associated Press)

When some #NeverTrump voices raised the possibility of a floor fight at the convention in Cleveland to dump Donald Trump they were ridiculed. Not anymore. Sen. Jeff Flake (Ariz.) got the ball rolling today.”Let’s face it: meet the old Trump, just like the new Trump. We’ve got what we’ve got. That’s not somebody who can win the White House. Where there’s no talk of a convention challenge or anything else, this might spur it.” That got a swift reaction from hopeful Trump opponents.

“All delegates should have the opportunity to vote their conscience given Trumps anti-constitution, anti-rule of law, and overtly racist campaign,” Tim Miller, a spokesman for the anti-Trump Our Principles PAC told me. “I think at this point it would be very unlikely he would lose the nomination but it’s important that the party and delegates have opportunity to voice dissent.”

A longtime Republican operative sensed the ground is shifting. “I don’t think we are there just yet,” he said. “But if Trump’s next 10 days are anything like his last 10 days, you would have to think that people are going to take a fresh look at finding either a realistic third option or fighting this out at convention.”

Then along comes Sen. Mark Kirk (Ill.)  who is the first elected official to un-endorse Trump. In a blistering statement he declared:

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.

And so will it begin — the rush to the exits? Trump surely is worried. He released a statement bizarrely claiming he never said that the judge’s Mexican heritage meant he could not do his job. The preposterous lie only underscores that his nomination might be at risk.

It is unfathomable to many political observers that Republicans are just now realizing they have an un-electable racist on their hands. Perhaps all they needed was an excuse to recover their decency and common sense. Could the delegates really throw open the convention and give the nomination to someone else? In any other year it would be unimaginable. Now, plenty of people are imagining just such a scenario.