Donald Trump’s runaway success in the GOP primaries so far is setting off alarm bells among neoconservatives who are worried he will not pursue the same bellicose foreign policy that has dominated Republican thinking for decades.

Neoconservative historian Robert Kagan — one of the prime intellectual backers of the Iraq War and an advocate for Syrian intervention — announced in the Washington Post last week that if Trump secures the nomination, “the only choice will be to vote for Hillary Clinton.”

Max Boot, an unrepentant supporter of the Iraq War, wrote in the Weekly Standard that a “Trump presidency would represent the death knell of America as a great power,” citing, among other things, Trump’s objection to a large American troop presence in South Korea.

Trump has done much to trigger the scorn of neocon pundits. He denounced the Iraq War as a mistake based on Bush administration lies, just prior to scoring a sizable victory in the South Carolina GOP primary. In last week’s contentious GOP presidential debate, he defended the concept of neutrality in the Israeli-Palestinian conflict, which is utterly taboo on the neocon right.

“It serves no purpose to say you have a good guy and a bad guy,” he said, pledging to take a neutral position in negotiating peace.

This set off his rival Marco Rubio, who replied, “The position you’ve taken is an anti-Israel position. … Because you cannot be an honest broker in a dispute between two sides in which one of the sides is constantly acting in bad faith.”

The Jerusalem Post suggested that Rubio’s assault on Trump’s views on the Middle East was designed to win Florida. If that’s the case, it’s apparently not working — in the Real Clear Politics averaging of GOP primary polls in the state, Trump is polling higher than he ever has.

In his quest to take up George W. Bush’s mantle, Rubio has arrayed a fleet of neoconservative funders, ranging from pro-Israel billionaire Paul Singer to Norman Braman, a billionaire auto dealer who funds Israeli settlements in the West Bank. His list of advisers is like a rolodex of Iraq War backers, ranging from Bush administration alumni Elliot Abrams and Stephen Hadley, to Kagan and serial war propagandist Bill Kristol.

Kristol also sits on the board of the Emergency Committee for Israel — a dark money group that assails candidates it perceives as insufficiently pro-Israel. The group started airing an ad this weekend against Trump portraying him as an ally to despots like Bashar Assad, Saddam Hussein, and Muammar Qaddafi — mostly because he argued that military invasions of Libya and Iraq left those countries worse off: