NBC NewsWire/Getty Images Hugh Hewitt has given up reluctantly supporting Donald Trump as the presumptive GOP nominee.

Conservative talk radio host Hugh Hewitt said on Wednesday that the Republican National Committee should ask Donald Trump to withdraw his candidacy or change the convention rules to prevent his formal nomination.

“The Republican National Committee needs to step in and step up and talk to him about getting out of the race,” Hewitt said on the Hugh Hewitt Show.

The alternative, he said, is a guaranteed victory for presumptive Democratic presidential nominee Hillary Clinton -- and the loss of Republican control of both houses of Congress.

“She’s gonna be president unless Republicans change their nominee,” Hewitt said. “When the dust clears we will have lost the House, we will have lost the Senate, we will have lost governorships."

Hewitt discussed the prospect of changing the Republican national convention rules to prevent the pledged delegates from voting Trump in on the first ballot.

“The Republican National Committee can do one thing: they can change the rules to make the first two ballots advisory,” Hewitt said.

He also suggested making the first ballot require a supermajority of votes.

“Make the delegates own it. If you are gonna commit suicide and someone is giving you a gun, don’t blame the gun, don’t blame the guy or the gal who gave you the gun -- blame yourself,” he concluded.

It is not clear how realistic Hewitt's rule changes, or the prospect of another candidate coming forward to replace Trump, are. Hewitt said he did not have a preferred substitute for Trump, but insisted that the real estate mogul not be the nominee.

Trump’s attacks on District Judge Gonzalo Curiel for his Mexican heritage are what drove Hewitt over the edge. Trump has faced increasing criticism from with the Republican party for claiming Curiel had a conflict of interest in presiding over a lawsuit against Trump University.

The conservative talk radio host was dissatisfied with Trump’s speech from a teleprompter on Tuesday night in which the candidate expressed regret that his comments about Curiel had been “misconstrued.”

"I have tried for 72 hours to wait for Donald Trump to extricate himself from this but he didn’t do it," Hewitt said Wednesday.

While Hewitt said he does not consider Trump a racist, he believes the presumptive GOP nominee is so indifferent to political norms that many Americans already think he is.

Hewitt was not previously a member of the “#NeverTrump” group of establishment Republicans, but he has used his platform to question Trump’s readiness early in the campaign.

In a September interview, Hewitt stumped Trump with detailed foreign policy questions, prompting the real estate mogul to call him a “third-rate radio announcer.”

Editor's note: Donald Trump regularly incites political violence and is a serial liar, rampant xenophobe, racist, misogynist and birther who has repeatedly pledged to ban all Muslims -- 1.6 billion members of an entire religion -- from entering the U.S.