Soon after former President Donald J. Trump took office, his staff explained how NATO’s mutual defense obligations worked.
“You mean, if Russia attacked Lithuania, we would go to war with Russia?” he responded. “That’s crazy.”
Mr. Trump has never believed in the fundamental one-for-all-and-all-for-one concept of the Atlantic alliance. Indeed, he spent much of his four-year presidency undermining it while strong-arming members into keeping their commitments to spend more on their own militaries with the threat that he would not come to their aid otherwise.
But he took it to a whole new level over the weekend, declaring at a rally in South Carolina that not only would he not defend European countries he deemed to be in arrears from an attack by Russia, but that he would go so far as to “encourage” Russia “to do whatever the hell they want” against them. Never before has a president of the United States — even a former one aspiring to reclaim the office — suggested that he would incite an enemy to attack American allies.
Some may discount that as typical Trump rally bluster or write it off as a poor attempt at humor. Others may even cheer the hard line against supposedly deadbeat allies who in this view have taken advantage of American friendship for too long. But Mr. Trump’s rhetoric foreshadows potentially far-reaching changes in the international order if he wins the White House again in November with unpredictable consequences.
What’s more, Mr. Trump’s riff once again raised uncomfortable questions about his taste in friends. Encouraging Russia to attack NATO allies, even if he were not fully serious, is a stunning statement that highlights his odd affinity for President Vladimir V. Putin, who has already proved his willingness to invade neighboring countries that do not have the protection of NATO.
Long averse to alliances of any kind, Mr. Trump in a second term could effectively end the security umbrella that has guarded friends in Europe, Asia, Latin America and the Middle East for much of the nearly eight decades since the end of World War II. Just the suggestion that the United States could not be depended on would negate the value of such alliances, prompt longtime friends to hedge and perhaps align with other powers, and embolden the likes of Mr. Putin and Xi Jinping of China.
“Russia and China have nothing to compare with America’s allies, and these allies depend on American commitment,” said Douglas E. Lute, a retired lieutenant general who served as ambassador to NATO under President Barack Obama and top adviser to President George W. Bush on the wars in Afghanistan and Iraq. “Casting doubt on the United States’ commitment to its allies sacrifices America’s greatest advantage over Russia and China, something that neither Putin nor Xi could achieve on his own.”
Undeterred by criticism of his latest comment, Mr. Trump doubled down on Sunday.
“No money in the form of foreign aid should be given to any country unless it is done as a loan, not just a giveaway,” he wrote on social media in all capital letters. “We should never give money anymore,” he added, “without the hope of a payback, or without ‘strings’ attached.”
Mr. Trump has long threatened to withdraw the United States from NATO and would no longer be surrounded by the kind of advisers who stopped him from doing so last time. He tried to pull American troops out of Germany at the end of his presidency in anger at Angela Merkel, then the chancellor, a withdrawal that was prevented only because President Biden came to office in time to rescind the decision.
At other points, Mr. Trump contemplated pulling American troops out of South Korea as well, only to be talked out of it, but has said since leaving office that such a move would be a priority in a second term unless South Korea paid more in compensation. Mr. Trump would also probably cut off military aid to Ukraine as it seeks to fend off Russian invaders, and he has offered no support for more aid to Israel in its war with Hamas.
Foreseeing the possibility of an American retreat from the world if Mr. Trump returns to office, Congress recently passed legislation barring any president from withdrawing from the NATO treaty without Senate approval. But Mr. Trump would not even need to formally quit the alliance to render it pointless.
And if the United States could not be counted on to come to the aid of partners in Europe, where it has the strongest historic ties, then other countries with mutual security agreements with Washington like Japan, the Philippines, Thailand, Australia, Argentina, Brazil, Chile, Colombia, Costa Rica and Panama could hardly be sure of American help, either.
Peter D. Feaver, a Duke University professor and former national security aide to Mr. Bush and President Bill Clinton, said Mr. Trump could reduce American troops in Europe to a level that “would render any military defense plans hollow” and “regularly poor-mouth the U.S. commitment” in a way that would convince Mr. Putin that he had free rein.
“Just doing those two things could wound and perhaps kill NATO,” Mr. Feaver said. “And few allies or partners in other parts of the world would trust any U.S. commitment after seeing us break NATO.”
History suggests this could result in more war, not less. When Dean Acheson, the secretary of state, described an American “defensive perimeter” in Asia in 1950 that did not include South Korea, North Korea invaded five months later, starting a bloody war that nonetheless pulled in the United States.
The signal from Mr. Trump to NATO allies like Poland, Finland, Estonia, Latvia and, yes, Lithuania is that they could be on their own by next January. Coming just days after Mr. Putin told Tucker Carlson that Poland was at fault for Adolf Hitler invading it in 1939, the mood in Warsaw could hardly be more unsettled.
“Article 5 has so far been invoked once — to help the U.S. in Afghanistan after 9/11,” Radek Sikorski, the foreign minister of Poland, noted in an email exchange on Sunday. “Poland sent a brigade for a decade. We did not send a bill to Washington.”
Jason Miller, a spokesman for Mr. Trump, pushed back against critics on Sunday, saying that Europe had seen more war under Mr. Biden than it did under the former president.
“President Trump got our allies to increase their NATO spending by demanding they pay up, but Joe Biden went back to letting them take advantage of the American taxpayer,” he said. “When you don’t pay your defense spending, you can’t be surprised that you get more war.”
The scorn for NATO that Mr. Trump expresses is based on a false premise that he has repeated for years even after being corrected, a sign that he is either incapable of processing information that conflicts with an idée fixe in his head or willing to distort facts to suit his preferred narrative.
As he has many times, Mr. Trump on Saturday castigated NATO partners that he called “delinquent” in paying for American protection. “You’ve got to pay,” he said. “You got to pay your bills.”
What Mr. Trump is referring to misleadingly is a nonbinding goal set by NATO defense ministers in 2006 that each member spend 2 percent of its gross domestic product on its own military, a standard ratified by NATO leaders in 2014 with the aspiration of achieving it by 2024. As of last year, just 11 of the 31 members, including Poland and Lithuania, had achieved that level, one more than under Mr. Trump. Last summer, NATO leaders pledged an “enduring commitment” to finally reaching the target. But even those who have not followed through do not actually owe money to the United States as a result.
NATO military spending is a legitimate concern, according to national security veterans, and Mr. Trump is not the first president to press NATO partners to do more — Mr. Bush and Mr. Obama did as well. But Mr. Trump is the first to present the alliance as a sort of protection racket where those who do not “pay up” will be abandoned by the United States, much less subject to attack by Russia with Washington’s encouragement.
“The credibility of NATO rests on the credibility of the man that occupies the Oval Office, since it’s the decisions taken there that in a critical situation will be decisive,” said Carl Bildt, a former prime minister of Sweden, which is completing its accession to NATO as the 32nd member.
“This applies to what could be crisis management in a minor engagement of some sort to the ultimate issue of the nuclear deterrent,” he said. “If Putin threatened nuclear strikes against Poland, would Trump say that he doesn’t care?”
Mr. Trump’s fixation on being paid by allies extends beyond Europe. At one point he assailed the mutual defense treaty with Japan that has been in force since 1951, and at other points he prepared to order U.S. troops out of South Korea. During an interview in 2021 shortly after leaving office, he made clear that if he returned to power, he would demand that South Korea pay billions of dollars more each year to keep American troops there.
National security veterans of both parties said that kind of thinking misunderstood the value of the alliances for the United States. It is a benefit to Americans, they say, to have overseas bases in places like Germany and South Korea that enable quick responses to crises around the world. It also deters adventurism by outcast states like North Korea.
“America’s commitment to its allies is not altruism or charity, but serves a vital national interest,” Mr. Lute said.
The uncertainty that would result from Mr. Trump’s lack of commitment, according to national security specialists, would lead to volatility unseen in years.
“The only saving grace,” Mr. Bildt said, “is that he will probably be so unreliable and unpredictable that even the Kremlin would be somewhat uncertain. But they would know that they have a fair chance of playing him politically in any crisis.”