WASHINGTON — Republican and Democratic senators on Monday distanced themselves from comments Donald Trump made about NATO over the weekend, when the GOP front-runner said the United States might not assist those countries should Russia expand its war in Europe.

Speaking at a rally in South Carolina, Trump recalled a conversation he had when he was president with an unnamed leader of a NATO country, who at the time was expressing concerns about Russia’s military plans.

“One of the presidents of a big country stood up and said, ‘Well, sir, if we don’t pay and we’re attacked by Russia, would you protect us?’ I said, ‘You didn’t pay, you’re delinquent?’ He said, ‘yes,’” Trump said. “No, I would not protect you. In fact, I would encourage them to do whatever the hell they want. You’ve got to pay.”

The remarks this weekend and comments Trump made throughout his time in the Oval Office about the North Atlantic Treaty Organization provoked frustration among some Republican senators who say they believe the organization is important for Western democracy as well as American national security.

Iowa Republican Sen. Chuck Grassley said in a brief interview Monday that he would encourage Trump not to make positive comments about Russia or similarly aligned countries.

“I think the best advice I could give to our presidential candidate, Trump, is simply to say, ‘Don’t say anything nice about any communist,’” Grassley said, listing off Russia’s Vladimir Putin, China’s Xi Jinping and North Korea’s Kim Jong Un.

Grassley said “it’s pretty simple” that the United States should not “appease” anyone like Putin, who he alleged is a “war criminal.”

“Why would you want to give any encouragement to him?” Grassley said of Putin.

Oklahoma Republican Sen. James Lankford noted that Congress has put “guardrails” on involvement in NATO, including that a president cannot withdraw the U.S. from the alliance without a two-thirds vote by the Senate.

Lankford said it shouldn’t be necessary for lawmakers to pass legislation to ensure intelligence sharing or active participation in NATO.

“We shouldn’t have to do that. The president of the United States should actually want to stick with our alliances,” Lankford said, noting that he disagrees with what Trump said over the weekend.

“I don’t agree, by any means, that we should turn away from our allies,” Lankford said.

No NATO withdrawal without Senate vote

Senate Armed Services Chairman Jack Reed, a Rhode Island Democrat, said there are numerous factors determining when and how the U.S. participates in NATO and that those “generally run” through the Defense Department and the president of the United States.

It would be possible, Reed said, for the president not to staff key positions or to remove U.S. troops from Europe. But, Reed said that Congress added language to the annual defense authorization bill last year that would prevent a president from formally withdrawing from NATO without a vote by the U.S. Senate.

“So we’d still be in NATO, but the president would have so many different levers that our participation could be diminished,” Reed said.

That provision, originally a bill sponsored by Virginia Democratic Sen. Tim Kaine and Florida Republican Sen. Marco Rubio, says the president “shall not suspend, terminate, denounce, or withdraw” the U.S. from NATO without a two-thirds vote by the Senate.

West Virginia Republican Sen. Shelley Moore Capito said Congress is “very supportive of NATO.”

“They’ve shown themselves to be a very strong force, upping their commitments,” Capito said. “So I think that’s a strong alliance and I would hope President Trump would agree with that.”

Capito said she didn’t think Congress needed to put any provisions in place to reinforce the United States’ commitment to NATO.

Senate Defense Appropriations Chair Jon Tester, a Montana Democrat, said Trump’s comments were “not a smart thing to say and not a smart thing to imply.”

A second term for Trump, should he win November’s election, could see “far worse” than the former president blocking the U.S. from assisting NATO allies should Russia attack them, Tester said.

Iowa Republican Sen. Joni Ernst said Congress “shouldn’t encourage anything like that” when asked about Trump’s comments.

“Obviously, the Europeans are our partners. We’ll continue to encourage them to contribute to NATO and do better,” Ernst said.

Lawmakers aren’t yet at the point where they need to add additional legal guardrails for what presidents can or cannot do on NATO, she said.

“We’re not at that point yet,” Ernst said. “I do support NATO. I think it plays a very important function and we can see why. So let’s just stay the course.”

Peters: ‘Unhinged’

Michigan Democratic Sen. Gary Peters, chair of the Democratic Senatorial Campaign Committee, said Trump’s comments were “ridiculous and irresponsible.”

“It disqualifies him from being president in my mind,” Peters said, adding he hopes voters will see “how unhinged he is.”

Ohio Democratic Sen. Sherrod Brown said he believes lawmakers need to focus on assisting Ukraine’s military so that Russia cannot get closer to NATO countries.

“To me, the focus needs to be protecting NATO,” Brown said. “The focus needs to be on not allowing Russia, who has a history of this, to overrun Ukraine, so that they bump up against NATO, because we know what that means for sending American troops. And that is so wrong and we would ever get in a position where that could happen.”

Kansas Republican Sen. Jerry Moran said NATO is “an important ally and we need to be united as we combat many of the world’s challenges together.”

Moran shrugged his shoulders when asked if there’s a way for Republicans to convince Trump that NATO is a beneficial alliance.

Maine independent Sen. Angus King said he thought it was “shocking that (Trump) would actively encourage Russian aggression in Europe.”

“If I had not seen it in print, I wouldn’t have believed it — that a U.S. president or U.S. public figure would say such a thing,” King added.

Indiana Republican Sen. Todd Young said that Congress could “continue to instill confidence in our NATO allies by passing” the emergency spending bill for Ukraine, Israel and Taiwan.

Arizona Democratic Sen. Mark Kelly said Trump’s comments make “us less safe.”

“I guess you could argue that he could be inviting Russia to attack one of our allies,” Kelly said. “That’s a threat to our own national security.”

Tuberville says allies should pay their share

Alabama Republican Sen. Tommy Tuberville sought to downplay Trump’s comments as being about NATO countries spending more on their defense capacities.

“You know, he stood up for American citizens when he was president, telling Europe, ‘Pay your share.’ That’s all they want, pay your share,” Tuberville said. “And some of the new ones already pay their share, that’s good. But you got some that don’t come close to spending the 2%, so it’s all sarcasm.”

Tuberville said he’s “all for NATO” if the countries meet that benchmark of investing at least 2% of their gross domestic product in their military

Hawaii Democratic Sen. Brian Schatz that he doesn’t believe anyone “can credibly claim that (Trump) doesn’t know what he’s saying and that he doesn’t intend to do what he’s talking about.”

“It’s now almost a decade into the Trump political experiment and we know exactly how he feels about Europe and Putin,” Schatz said. “And we should stop pretending otherwise just because we’re afraid of getting criticized by the pundits who don’t like us focusing on Russia.”

Louisiana Republican Sen. John Kennedy, unlike many of his Republican colleagues, declined to answer questions about Trump’s comments.

“I don’t have anything for you on that,” Kennedy said.

Nikki Haley, U.N. ambassador during the Trump administration and his main challenger left in the 2024 Republican presidential primary, admonished the former president during a campaign event in South Carolina on Monday, saying that she was “appalled” when she heard what he said about NATO.

“The idea that he said he would side with (Putin) over our allies who were with us after 9/11 — I mean, that’s not somebody who’s going to prevent a war, that’s somebody who’s going to get us in a war,” Haley said. “And that kind of rhetoric was unhinged.”

What is NATO and what does it do?

The North Atlantic Treaty Organization was founded in 1949 following World War II and is designed around several core principles, including that if one nation is attacked, the provocation is seen as an attack on all member countries.

That provision, known as Article 5, has been invoked only once in the alliance’s history — by the United States following the 9/11 terrorist attacks.

NATO currently includes 31 member countries, including Canada, France, Finland, Germany, Italy, Poland, Spain and the United Kingdom.

The alliance has been instrumental in aiding Ukraine after Russia invaded and launched a war more than two years ago.

The United States and other countries have provided billions in military, humanitarian and economic support to Ukraine as its military has held off Russian troops from overrunning their country.

While Ukraine isn’t a NATO member, it has sought to join in the past and current President Volodymyr Zelenskyy has pressed for his country’s inclusion throughout the war.

The NATO alliance considers stopping Putin in Ukraine essential to avoiding a wider, deadlier conflict than the one already underway.

Numerous heads of state, including President Joe Biden, have warned that if Putin is allowed to overtake Ukraine, he would likely seek to overtake other Eastern European countries, many of which belong to NATO.

Such an attack would likely lead to a direct war between NATO countries and Russia in Europe. That would undoubtedly include the U.S. troops.

Military spending by NATO countries

Trump repeatedly criticized NATO allies during his first term in office for what he claims is a lack of military spending on their part.

NATO countries are supposed to spend 2% of their gross domestic product on the country’s military budget, but because the nations in the alliance all have vastly different sized economies, their contributions to their own defense budgets range in terms of dollar for dollar investments. That agreement was reached in 2006 with a deadline for implementation by 2024.

NATO says on its website that the number of NATO member countries spending at least 2% of their GDP on defense has risen from three in 2014 to seven in 2022.

“While the 2% of GDP guideline alone is no guarantee that money will be spent in the most effective and efficient way to acquire and deploy modern capabilities, it remains an important indicator of the political resolve of individual Allies to devote to defense a relatively small but still significant level of resources,” the website says.

Skylar Laird contributed to this report.