“I don’t remember anything like this in my lifetime of effectively 30 years in Republican Party politics,” said Bruce Haynes, a GOP operative in Washington. “People don’t know what to do. They call me in tears and say, ‘I can’t vote for him because he’s a liar, a cheat and a racist and yet everything I’ve ever cared for in politics is on the line and could be lost if I don’t vote for him.’”

While American history is replete with presidential nominees who’ve been less than welcomed by their party’s power brokers, never in recent memory have so many prominent politicians vowed not to support a candidate who’s increasingly a lock to top their ticket.

“There is someone now leading the pack who could destroy the party and lose an election that should be ours,” said former Minnesota Sen. Norm Coleman.

But the establishment clearly waited too long for its collective freak out. Trump had won three of the first four nominating contests before Republicans finally washed away months of magical thinking that the political newcomer who’s led the polls since the summer would somehow collapse on his own. The Republican donor class, after pouring more than $100 million into Jeb Bush’s super PAC, is redoubling its efforts to halt Trump, deciding this week to beef up the operations of Our Principles PAC, which was created in January to attack Trump.