This article is more than 2 years old.

May 4, 2016 This article is more than 2 years old.

Donald Trump has won the Republican primary in Indiana and, with that, effectively clinched his party’s nomination. The head of the Republican party took to Twitter with a call for the party to unite behind the presumptive candidate.

But many of Trump’s conservative detractors are headed in the other direction, warning the nomination will signal the end of the Republican Party. One of the most prominent critics is Lindsey Graham, the senator from South Carolina:

The Republican senator from Nebraska, Ben Sasse, took the opportunity to re-circulate his passionately written essay that declared “A presidential candidate who boasts about what he’ll do during his ‘reign’ and refuses to condemn the KKK cannot lead a conservative movement in America.”

An advisor to John McCain’s campaign pledged to vote for Hillary Clinton:

Ronald Reagan’s son declared the party no longer had anything to do with his father.

And various conservative radio show hosts, pundits, and journalists made no secret of their horror at the prospect of President Trump, with many pledging to leave the party.

Contributors to conservative blog RedState were among the most vociferous:

And the managing editor of the Washington Examiner, a conservative who has battled hard against Obamacare, tweeted proof he had left the Republican Party.

It’s impossible to know tonight how widely-shared these sentiments are, whether these voters will stay away for good, or whether Trump will attract more voters to the polls in November than he is driving away from the Republican party now. What’s clear is some Republicans are currently unwilling to support a Trump presidency under any circumstances.