WASHINGTON — There are few things that President Vladimir V. Putin of Russia desires more than the weakening of NATO, the military alliance among the United States, Europe and Canada that has deterred Soviet and Russian aggression for 70 years.
Last year, President Trump suggested a move tantamount to destroying NATO: the withdrawal of the United States.
Senior administration officials told The New York Times that several times over the course of 2018, Mr. Trump privately said he wanted to withdraw from the North Atlantic Treaty Organization. Current and former officials who support the alliance said they feared Mr. Trump could return to his threat as allied military spending continued to lag behind the goals the president had set.
In the days around a tumultuous NATO summit meeting last summer, they said, Mr. Trump told his top national security officials that he did not see the point of the military alliance, which he presented as a drain on the United States.
At the time, Mr. Trump’s national security team, including Jim Mattis, then the defense secretary, and John R. Bolton, the national security adviser, scrambled to keep American strategy on track without mention of a withdrawal that would drastically reduce Washington’s influence in Europe and could embolden Russia for decades.
Now, the president’s repeatedly stated desire to withdraw from NATO is raising new worries among national security officials amid growing concern about Mr. Trump’s efforts to keep his meetings with Mr. Putin secret from even his own aides, and an F.B.I. investigation into the administration’s Russia ties.
A move to withdraw from the alliance, in place since 1949, “would be one of the most damaging things that any president could do to U.S. interests,” said Michèle A. Flournoy, an under secretary of defense under President Barack Obama.
“It would destroy 70-plus years of painstaking work across multiple administrations, Republican and Democratic, to create perhaps the most powerful and advantageous alliance in history,” Ms. Flournoy said in an interview. “And it would be the wildest success that Vladimir Putin could dream of.”
Retired Adm. James G. Stavridis, the former supreme allied commander of NATO, said an American withdrawal from the alliance would be “a geopolitical mistake of epic proportion.”
“Even discussing the idea of leaving NATO — let alone actually doing so — would be the gift of the century for Putin,” Admiral Stavridis said.
Senior Trump administration officials discussed the internal and highly sensitive efforts to preserve the military alliance on condition of anonymity.
After the White House was asked for comment on Monday, a senior administration official pointed to Mr. Trump’s remarks in July when he called the United States’ commitment to NATO “very strong” and the alliance “very important.” The official declined to comment further.
American national security officials believe that Russia has largely focused on undermining solidarity between the United States and Europe after it annexed Crimea in 2014. Its goal was to upend NATO, which Moscow views as a threat.
Russia’s meddling in American elections and its efforts to prevent former satellite states from joining the alliance have aimed to weaken what it views as an enemy next door, the American officials said. With a weakened NATO, they said, Mr. Putin would have more freedom to behave as he wishes, setting up Russia as a counterweight to Europe and the United States.
An American withdrawal from the alliance would accomplish all that Mr. Putin has been trying to put into motion, the officials said — essentially, doing the Russian leader’s hardest and most critical work for him.
When Mr. Trump first raised the possibility of leaving the alliance, senior administration officials were unsure if he was serious. He has returned to the idea several times, officials said increasing their worries.
Mr. Trump’s dislike of alliances abroad and American commitments to international organizations is no secret.
The president has repeatedly and publicly challenged or withdrawn from a number of military and economic partnerships, from the Paris climate accord to an Asia-Pacific trade pact. He has questioned the United States’ military alliance with South Korea and Japan, and he has announced a withdrawal of American troops from Syria without first consulting allies in the American-led coalition to defeat the Islamic State.
NATO had planned to hold a leaders meeting in Washington to mark its 70th anniversary in April, akin to the 50-year celebration that was hosted by President Bill Clinton in 1999. But this year’s meeting has been downgraded to a foreign ministers gathering, as some diplomats feared that Mr. Trump could use a Washington summit meeting to renew his attacks on the alliance.
Leaders are now scheduled to meet at the end of 2019, but not in Washington. Continue: Trump Discussed Pulling U.S. From NATO, Aides Say Amid New Concerns Over Russia