(CNN) President Donald Trump undermined his own senior officials, frustrated Republican allies , alarmed arms control specialists and further angered members of the military with remarks Wednesday -- many of them flatly false -- about Turkey's attack on Kurds once allied with the US in Syria.

Trump also appeared to confirm the existence of nuclear weapons on Turkish soil , despite Pentagon policy not to comment on the weapons' presence anywhere outside US territory.

As Trump emphatically doubled down on his decision to pull US troops back from northeastern Syria, effectively giving Turkish President Recep Tayyip Erdogan clearance to launch his offensive , Republicans worried that he may pay a political price.

Speaking in the Oval Office on Wednesday, Trump claimed that US soldiers are "not in harm's way" as Turkey advances into northeastern Syria, that American troops there will return to the US and that the Kurds who fought for and alongside the US to defeat ISIS "are much safer now." None of those claims are true.

'Nothing to do with us'

Even as he sent his vice president and secretary of state to Turkey on Wednesday to negotiate a ceasefire, Trump kneecapped their bargaining power by publicly declaring that the area in question has "nothing to do with us."

Republicans in a closed-door meeting Wednesday with Defense Secretary Mark Esper vehemently disagreed . Some vented that Trump's move was the worst foreign policy decision they'd ever seen, while others applauded the criticisms.

Outside the room, a Trump ally predicted the foreign policy debacle could do domestic damage.

"He's making the biggest mistake of his presidency," said Sen. Lindsey Graham . "I hope the President will correct the message he sending. ... It's devastating to our allies, it's going to eventually be devastating to Israel. It's going to be well received in Tehran, it's going to be well received in Moscow."

The South Carolina Republican said evangelical Christians, who form part of Trump's base and who care about the protection Kurds extended to Christians in the region, would take note. "I think in a democracy you'll be held accountable," he said.

The breadth of the anger about Trump's decision is unprecedented in his presidency. "I've never seen anything like it, frankly, with respect to bipartisan consensus ," said Aaron David Miller, a senior fellow at the Carnegie Endowment for International Peace.

That, said Nora Bensahel, a visiting professor of strategic studies at Johns Hopkins School of Advanced International Studies, is because "the strategic implications are so very clear and so damaging across the board to US security interests. There's no strategic upside to this decision."

The President has tried to manage the fallout, announcing Tuesday that Vice President Mike Pence and Secretary of State Mike Pompeo would travel to Turkey to insist on a ceasefire. But it became clear that Republicans such as Graham wouldn't see the course correction they want.

Pompeo told Fox Business News on Wednesday that he and Pence "need to have this conversation with [Erdogan] directly ... he needs to stop the incursion into Syria."

Just a few hours later, Trump declared that "if Turkey goes into Syria, it is between Turkey and Syria. It's not our problem."

The President "completely undercut" Pence and Pompeo, Graham said on Twitter.

Domestic agenda

"I felt we had in motion a plan that would probably work, you know, Pompeo and Pence going over to give a message to Turkey," Graham later told CNN's Suzanne Malveaux. "He needs to restore their ability to end the bloodshed."

In the Oval Office, Trump also denied that Erdogan had dismissed the possibility of a ceasefire. "He didn't say that at all," the President declared. On Tuesday, Erdogan said, "We will never declare a ceasefire ."

Trump dug in as Wednesday wore on, repeating statements that ignored facts or opinions that run counter to his narrative -- even contradicting statements he himself had made just days earlier.

Pompeo shed some light Wednesday on the President's decision to pursue a course that lawmakers and Pentagon and State Department officials strongly opposed. "My experience with the President is that he makes decisions and then absorbs data and facts. ... The President is always very focused on what's the objective," Pompeo told Fox Business.

The objective in this case, analysts declared, is Trump's political agenda, not US national security.

'Not in harm's way'

"He did this primarily for reasons of his own domestic politics," Miller said, pointing to the President's campaign promises to bring troops home. Trump's string of false statements Wednesday is "all part of his effort to gaslight, create an alternate reality. He's betting that if he does it enough, maybe the people who count in his eyes -- his base -- will believe it."

Speaking in the Oval Office, Trump said US soldiers are "not in harm's way" as Turkey advances into northeastern Syria.

"That is definitively not true," Bensahel said. Pentagon sources confirm this, saying the troops are in a high-risk situation and that the Defense Department's overriding priority right now is to ensure they are removed safely.

Hundreds of troops remain in the region and "cannot be withdrawn instantaneously," Bensahel said. "They are at risk from Turkish-backed forces in the region. If Turkey's forces are going into Syrian territory, there are risks to US personnel about being caught in the middle."

Trump also said he's bringing those troops "back home." Two days ago, he issued a statement saying those troops will be redeployed to other parts of the Middle East, with many moving to Iraq.

In a claim that drew particular anger, Trump said that "the Kurds are much safer now" and added that "they're not angels" during an Oval Office meeting with Italian President Sergio Mattarella.

CNN reporters Arwa Damon on the Turkish-Syrian border and Nick Paton Walsh in Erbil, Iraq, have reported that the death toll is climbing as clashes continue in Turkey's "Operation Peace Spring." Aid agencies describe the Kurdish men, women and children fleeing Turkish forces as a humanitarian disaster.

"I don't know what parallel alternate universe the President operates in," said Sen. Robert Menendez, a New Jersey Democrat. "The Kurds are not safer."

Sen. Tim Kaine, a Virginia Democrat, touched on the sensitive issue of honor that drives much military anger about the President's decision, saying that Trump's "trash talking" about the Kurds is "just so insulting."

'Ashamed'

"I'm on the Armed Services Committee and I know how our military leaders feel about this," Kaine said. "They are just ashamed that the US would abandon a battlefield ally. ... This is just completely contrary to the ethos of, you don't leave a battlefield colleague behind."

Trump also declared that the fighting in Syria has "nothing to do with us."

"It does," Bensahel countered, "in that the United States is a target of the Islamic State and our close allies are a target of Islamic State's."

The US went into Syria "to help local forces establish some sort of security in the area, ostensibly because of the threat from the Islamic State, which had been operating freely in the area before the United States entered."

For Italy's President, with Trump at the White House on Wednesday, the threat is not abstract. An ISIS sympathizer attacked a soldier at Milan's Central Station in May 2017. Mattarella said his country is deeply concerned about Turkey's incursion because it allows ISIS a chance to grow.

Sen. Diane Feinstein, a California Democrat, raised the risk that the thousands of ISIS fighters jailed by the Kurds could be released, "returning to the fight and carrying out terrorist attacks abroad."