Trump has made a long list of curious statements on foreign policy. In a recent debate, he didn’t seem to know about the “nuclear triad” — the nuclear-armed bombers, land-based missiles and submarines that make up the U.S. atomic arsenal. He has confused the F-35 fighter jet with the Long-Range Strike Bomber, and the Kurds with Iran’s Quds Force. He’s said he gets military advice watching television, has praised U.S. foes like Russian President Vladimir Putin and has shown no apparent interest in seeking the counsel of the party’s national security sages.

“He wouldn’t just get an F — he’d get a zero,” said Richard Fontaine, president of the Center for a New American Security, who is backing Florida Gov. Jeb Bush and is a former top aide to Sen. John McCain, the 2008 GOP presidential nominee who now chairs the Armed Services Committee.

A who’s who of GOP defense bigwigs have disparaged Trump’s national security missives. Former CIA Director Michael Hayden said in October that he was “troubled by a whole series of his statements.” Former Defense Secretary Robert Gates wrote an op-ed, “The kind of president we need,” which said: “Primal screaming may be good therapy, but it is a poor substitute for practical politics.”

And McCain, whom Trump mocked last year for having been a prisoner of war in Vietnam, has repeatedly slammed Trump’s claim that he’ll convince Mexico to pay for a wall along the U.S. southern border. “If he’s the nominee, he’ll have a pretty steep learning curve. I think that’s pretty obvious,” McCain told POLITICO.

Trump has argued that he is the best candidate in the Republican field for the military, and that his business background would help root out waste at the Pentagon. During a national security speech he delivered in September on the retired battleship USS Iowa, he vowed that he would build up the military “so big and so strong and so great, and it will be so powerful that I don’t think we’re ever going to have to use it.”

But in the view of the GOP defense establishment, Trump has emerged as a key threat to the party’s strategy to make national security and foreign policy a cornerstone of the race for the White House, as well as the case against Clinton.

Indeed, at the Reagan Forum, the assembled experts dismissed both Trump and rival candidate Ben Carson as little more than a bad joke in panel after panel, offering the mantra that both anti-establishment campaigns would falter once voters started paying attention to national security.

Then came November’s deadly terrorist attacks in Paris and December’s mass shooting in San Bernardino, Calif., which placed terrorism high on the list of voter concerns. But while Carson stumbled, as predicted, Trump has only grown stronger with Republican primary voters.

“Obviously, nobody really took Trump seriously for quite time. Now, of course, he can’t be ignored,” said Dov Zakheim, who was a senior foreign policy adviser to former President George W. Bush and served as the Pentagon’s budget chief in the Bush administration. He is not backing any candidate in the 2016 race.

Also galling to longtime GOP defense leaders: Unlike the other candidates, Trump does not appear to have reached out to any of the traditional advisers on foreign policy and national security. Analysts at the major conservative think tanks and others who have briefed 2016 candidates say they’ve heard nothing from Trump’s campaign — and know no one advising him.

“Absolutely none that I am aware of,” said Eric Edelman, an adviser to 2012 GOP presidential nominee Mitt Romney who co-founded the John Hay Initiative, which has briefed multiple candidates and offered a foreign policy playbook to all of the 2016 field.

Even outreach initiated by the defense community has gone nowhere.

Mackenzie Eaglen of American Enterprise Institute said she asked for a meeting with the Trump campaign this month to talk military issues, and sent them AEI’s defense strategy. The campaign was not interested.

“I got back the most classic letter, thanking me for being a supporter and sending the strategy,” said Eaglen, who has briefed several other candidates and was advising Wisconsin Gov. Scott Walker.

Trump’s disinterest in boning up on foreign policy is hardly unique to those issues. Shunning Washington insiders has been a key element of Trump’s campaign playbook that’s riled up a conservative base angry with Republicans and Democrats alike in Washington.

“The so-called insiders within the Washington ruling class are the people who got us into this trouble. So why should we continue to pay attention to them?” Trump wrote in his recent book “Crippled America.”

In a general election, Republicans worry that Clinton’s long record on foreign policy as secretary of state will provide a clear contrast to Trump — akin to Clinton’s “3 a.m. phone call” ad in the 2008 Democratic presidential primary — and allow Clinton to avoid a long list of vulnerabilities in her foreign policy record. At the same time, they hold out at least some hope that Trump’s skills as a counter-puncher could still prove formidable if he’s the nominee.

“He’s got a real knack and an instinct for sussing out people’s vulnerabilities and going after them very, very effectively,” said Edelman, who added he’s not supporting Trump or any other specific GOP candidate.

Trump has claimed some military advisers — sort of.

In the same interview in which Trump said, “I watch the shows,” when asked where he gets his military advice, he ticked off the names of former U.S. Ambassador to the United Nations John Bolton and retired Col. Jack Jacobs, an NBC News military analyst. A spokesman for Bolton said the two spoke during the 2014 election cycle when Trump donated to Bolton’s political action committee, but not since. And Jacobs told Mother Jones that he has not consulted on national security issues with Trump.

Trump vowed in September that he would soon unveil his national security team, and he made the pledge again in an October interview with conservative radio host Hugh Hewitt. “I do have a great group of people, and at the right time, I’m going to roll them out,” Trump told Hewitt.

That rollout has not happened.

On the campaign trail, Trump talks tough on foreign policy, just like much of the Republican field. In his speeches, he frequently invokes famous U.S. Gens. George Patton and Douglas MacArthur to contrast with President Barack Obama’s military team. He’s vowed to pummel the Islamic State and take their oil — “I would bomb the s--- out of them,” he said at a November Iowa rally — while playing up his opposition to the initial Iraq invasion in 2003.

But to the party’s security and defense experts, Trump’s knowledge gap on military issues in interviews and debates has been cringe-worthy.

He was stumped by a question at December’s CNN debate — also from Hewitt — on what he would do about the “nuclear triad,” appearing not to understand the question.

“I think, for me, nuclear is just the power, the devastation is very important to me,” he said.

Hewitt has been the source of multiple Trump foreign policy blunders. On his radio show, he asked Trump about the Quds Force in one interview, but the candidate thought he was referring to the Kurds. (Trump says he misheard Hewitt’s “gotcha question.”) Another time, Hewitt asked Trump about the next-generation bomber, only to get a response from Trump about pilots criticizing the F-35 fighter.

The 2016 campaigns are bashing Trump’s foreign policy statements as they try to chip into his lead. Bush’s largest super PAC released an ad in December bashing Trump for saying he gets his military advice by watching “the shows.”

“It is certainly relevant to voters,” Texas Sen. Ted Cruz said in an interview with Hewitt this month. “Does a potential commander in chief know what the nuclear triad is, much less is he or she prepared and able to strengthen it and keep this country safe?”

Trump’s campaign did not respond to requests for comment.

Republican defense pundits have also become more vocal. A slew of opinion articles have taken on Trump, such as former McCain speechwriter Mark Salter’s “We Deserve Better Than Donald Trump” and John Bellinger’s “Donald Trump is a danger to our national security.”

Bellinger, a legal adviser to George W. Bush’s National Security Council and State Department, argued that Trump’s call to ban Muslims from entering the U.S. isn’t just harmful to Republicans in the campaign, but is already damaging U.S. interests abroad and making the country less safe.

“It is amazing to me that Donald Trump seems to be utterly disinterested in the details of difficult defense or national security or foreign policy issues,” said Bellinger, who is backing Jeb Bush.

Trump has said he’ll be prepared on foreign policy when he takes office, but unsurprisingly, the GOP defense community isn’t buying it.

“I don’t think it’s so terrible that Trump doesn’t know a lot about foreign policy and national security,” said Elliott Abrams of the Council on Foreign Relations, a former aide in the Reagan and George W. Bush administrations who has briefed a half-dozen GOP hopefuls. “What’s troubling is that he doesn’t know that he doesn’t know anything about national security. He thinks he knows a lot about national security, so he is spending zero time learning. That’s the worrying thing.”