Donald Trump’s ascent in the Republican presidential race has presented one group of Republicans with something more than just concern about the fate of their party. For neoconservatives, a Trump nomination could mean an extension of their sentence in a political Siberia.

Some members of this hawkish cohort saw the 2016 election as an opportunity to find a way in from the cold, where they have been largely sidelined since playing a key role as boosters of the second Bush administration’s ill-fated invasion of Iraq in 2003.

Trump made clear his own view of that war — at least now, 13 years later — at the Republican presidential debate in Greenville, South Carolina on February 13, when, to the shock of GOP traditionalists in the audience, he declared, “Obviously the war in Iraq was a big, fat mistake.” Then, twisting the knife deeper, he added: “We should have never been in Iraq. They lied, they said there were weapons of mass destruction. There were none, and they knew that there were none.”

For neoconservatives, this, along with Trump’s comments about staying “neutral” in the standoff between Israel and the Palestinians so as to preserve his credibility as a mediator, told them all they needed to know. A Trump presidency, they believe, would be a death knell for restoring their vision of promoting democracy and American values through a stronger U.S. military role in the world and, in particular, in the Middle East.

Now, after first hitching their wagons to Jeb Bush’s failed candidacy, many neoconservatives are flocking to Marco Rubio’s camp. Even as the U.S. senator from Florida finds his hopes of winning the GOP presidential primary fading, neoconservatives see Rubio as perhaps their best chance of countering the isolationist policy they see emerging from a possible Trump presidency.

Rubio’s national security advisory council, announced on March 7, is chockablock with neoconservatives and former Bush administration defense officials, many of them Jewish, including Elliott Abrams, Eliot Cohen, Michael Chertoff, Michael Mukasey and Dan Senor.

“I’d vote for Hillary Clinton rather than Trump or Cruz,” said Kenneth Adelman, a Reagan administration veteran who was a Pentagon adviser during the Iraq War, which he famously predicted beforehand “would be a cakewalk.”

“Voting for Clinton isn’t something I want to do,” he told the Forward, “but it’s better than voting for Cruz or Trump.”

In their heyday, during the presidency of George W. Bush, neoconservatives served in senior positions in the White House and the Pentagon, and in influential think tanks close to the administration. Accused by critics of providing the ideological foundation for America’s decision to launch its war on Iraq, they saw Bush abandon the war’s grander aims in the last years of his tenure as the war itself unleashed havoc. The Bush administration’s latter-day policy of merely managing the ongoing conflicts in Iraq and Afghanistan then gave way under President Obama to a policy of minimizing overseas military intervention.

The upcoming elections initially seemed to offer neoconservatives renewed hope for restoring their worldview, in particular via Jeb Bush. Other defense hawks, who do not necessarily identify as neoconservative, also hoped for a candidate who would focus on promoting democracy and on expanding defense spending.

But Jeb Bush’s flameout despite his early lead in the polls has left Rubio as the only Republican candidate with a strong interest in foreign policy and a willingness to expand American military funds and forces overseas. He is also the only Republican candidate who has declared support for a democracy-promotion agenda.

“Rubio has always been very interested in questions of democracy and human rights,” said Elliott Abrams, former deputy national security adviser for George W. Bush. He noted Rubio’s insistence on requiring political reform in Cuba before normalizing relations with that country, as Obama has done. Abrams also cited proposed legislation Rubio co-authored that called for American assistance to Bahrain to be conditioned on more openness by that Middle East country’s monarchy toward its domestic opposition.

Abrams is also among the 18 former officials who make up Rubio’s national security council. So is Eric Edelman, who was undersecretary of defense in the Bush administration and filled many top diplomatic positions. But be careful about calling him a neoconservative.

“I hate this term,” he said. “In many circles in the U.S. it is a polite name for Jews.”

Edelman praised Rubio’s knowledge of foreign policy and the role he played on the Senate Foreign Relations Committee, as well as his “consistent support for American commitment and engagement in the world.”

Dov Zakheim, another member of the Rubio advisory team, sought to distinguish between the Florida senator and his main rival in countering Trump, Ted Cruz. “He’s a Johnny-come-lately to this issue,” Zakheim said of Cruz “His record on defense was of a deficit hawk before he became a defense hawk.”

This is a crucial point for those seeking a candidate supportive of a robust U.S. military posture. Cruz’s focus on eliminating waste in the military, along with his strict fiscal conservatism, is a source of concern for Republicans seeking an expansion of America’s role in the world.

All those throwing their support behind Rubio at this late stage of the game are well aware of the Florida senator’s poor performance thus far in the Republican primaries and of the questions regarding his political viability.

But if Rubio does go down, what next for neoconservatives and security-minded Republicans?

Many, like Abrams, would support a Cruz candidacy, though less enthusiastically, understanding that he may hesitate before spreading America’s wings of influence across the globe. Cruz’s chances are significantly better than those of Rubio, but he, too, is far behind Trump and, according to polls, has little chance of catching up as the primary race moves on.

Thinking the unthinkable, some neoconservatives and other Republican defense hawks are contemplating different paths.

The Brookings Institution’s Robert Kagan, a leading neoconservative, declared he’d vote for Clinton rather than voting for a Republican ticket topped by Trump.

Despite Clinton’s own record of voting for the Iraq War — which she now says was “a mistake” — and her unsuccessful arguments as secretary of state in the Obama administration for stronger U.S. action to stop the slaughter in Syria, this is one step too far for other neoconservatives. William Kristol, editor of The Weekly Standard, has instead been advocating for a third-party candidate, calling this a “one-time, emergency adjustment to the unfortunate circumstance (if it happens) of a Trump nomination.”

Abrams supports the idea of recruiting a third-party conservative, but he will also consider another option: staying out altogether. “I will never vote for Trump,” he said, recalling that in 1972, faced with the choice between Richard Nixon and George McGovern, he simply did not vote.

Edelman will not even entertain the possibility of a Rubio failure in the primaries. “I have great confidence in him,” he said. Asked where he will throw his support if this confidence turns out to be mistaken, Edelman said, “I’m not ready to burn this bridge yet.”

Contact Nathan Guttman at guttman@forward.com or on Twitter, @nathanguttman