Donald Trump calls the Iraq War a lie-fueled fiasco, admires Vladimir Putin and says he would be a "neutral" arbiter between Israel and the Palestinians. When it comes to America's global role he asks, "Why are we always at the forefront of everything?"

Even more than his economic positions, Trump's foreign policy views challenge GOP orthodoxy in fundamental ways. But while parts of the party establishment are resigning themselves or even backing Trump's runaway train, one group is bitterly digging in against him: the hawkish foreign policy elites known as neoconservatives.

In interviews with POLITICO, leading neocons — people who promoted the Iraq War, detest Putin and consider Israel's security non-negotiable — said Trump would be a disaster for U.S. foreign policy and vowed never to support him. So deep is their revulsion that several even say they could vote for Hillary Clinton over Trump in November.

"Hillary is the lesser evil, by a large margin," said Eliot Cohen, a former top State Department official under George W. Bush and a strategic theorist who argues for a muscular U.S. role abroad. Trump's election would be "an unmitigated disaster for American foreign policy," Cohen said, adding that "he has already damaged it considerably."

Cohen, an Iraq war backer who is often called a neoconservative but said he does not identify himself that way, said he would "strongly prefer a third party candidate" to Trump, but added: "Probably if absolutely no alternative: Hillary."

In a March 1 interview with Vox, Max Boot, a military historian at the Council on Foreign Relations who backed the Iraq War and often advocates a hawkish foreign policy, said that he, too, would vote for Clinton over Trump. "I'm literally losing sleep over Donald Trump," he said. "She would be vastly preferable to Trump."