Donald Trump’s comment that he once told a European leader he’d abandon NATO members to a Russian invasion if they hadn’t met defense-spending commitments prompted condemnation by the White House and alarm among allies — but also backing from supporters in Congress.

Trump’s anecdote at a campaign rally evoked the Republican front-runner’s past pressure campaign, particularly on European NATO members, as world leaders game out the policy repercussions if Trump were to win the U.S. presidential election in November.

Pushback from President Joe Biden’s administration was swift. “Encouraging invasions of our closest allies by murderous regimes is appalling and unhinged – and it endangers American national security, global stability, and our economy at home,” White House spokesman Andrew Bates said in a statement on Saturday night. Biden, in a statement by his reelection campaign, called Trump’s comments “appalling and dangerous.”

Trump’s comments on NATO send a “horrible message” to Russian President Vladimir Putin “and to America,” Democratic Sen. Joe Manchin said Sunday. His party colleague John Fetterman blasted them as “astonishing “ and “wild.”

Trump’s allies in the Senate on the other hand, defended his remarks. “I’m not worried about it at all,” said Sen. Lindsey Graham, a South Carolina Republican. “He’s not going to withdraw from NATO. The last thing Russia would do if Trump is president is start a war. He’s just trying to make a point.”

Trump said at a rally in South Carolina on Saturday that the decades-old military alliance was “busted” until he came along and forced members to “pay up.” When a leader at an unspecified NATO meeting asked if the U.S. would protect them if they were delinquent on spending, Trump said he responded by saying he would tell Russia to do “whatever the hell they want” to those who weren’t meeting their obligations.

Trump was “absolutely right” to pressure “our allies to start paying their bills,” Republican Sen. Thom Tillis told reporters.

Republican Sen. Marco Rubio said he had “zero concern” about the comments and that Trump was “telling a story” to drive home a point. The former president “doesn’t talk like a traditional politician,” Rubio said on CNN’s State of the Union. “And we have already been through this now.”

In Europe, NATO Secretary-General Jens Stoltenberg said in a statement on Sunday that the alliance remains “ready and able to defend all allies.”

“Any attack on NATO will be met with a united and forceful response,” he said. “Any suggestion that allies will not defend each other undermines all of our security, including that of the U.S., and puts American and European soldiers at increased risk.”

Stoltenberg said he expects “that regardless of who wins the presidential election, the U.S. will remain a strong and committed NATO ally.”

Still, there’s concern among officials from NATO members that Trump may be headed back to the White House as he rapidly closes in on the Republican nomination.

European Council President Charles Michel said in a post on X, formerly Twitter, that “reckless statements” about NATO’s security and solidarity only serve the interests of Russian President Vladimir Putin.

European Commissioner Thierry Breton told LCI television that Europe would be able to deal with the U.S. if Trump were elected, but that U.S. democracy was “sick.” “We in Europe cannot play heads or tails every four years depending on the outcome of this or that election,” he said.

Trump has already shown that “he values being close to Putin more than to democratic transatlantic partners, and is accordingly prepared to disregard international obligations,” Omid Nouripour, a co-leader of Germany’s Greens party and part of the ruling coalition, was quoted as saying Sunday by the Funke media group.

Trump on Saturday said Russia’s war in Ukraine must end and reiterated his disapproval for sending more aid overseas as the Senate seeks to move forward with a package to provide emergency funding for Ukraine and Israel.

“We got to get that war settled and I’ll get it settled,” Trump said at the rally.

With assistance from Stephanie Lai, Alicia Diaz, Ania Nussbaum, Iain Rogers, Colin Keatinge, Christine Burke, Natalia Drozdiak and Erik Wasson.