WASHINGTON — The United States is suspending one of the last major nuclear arms control treaties with Russia after heated conversations between the two powers recently failed to resolve a long-running accusation that Moscow is violating the Reagan-era treaty.
Secretary of State Mike Pompeo announced the decision on Friday as the Trump administration maintained that the Russian government has been unwilling to admit that a missile it has deployed near European borders violates the terms of the 1987 Intermediate-Range Nuclear Forces Treaty.
Mr. Pompeo and his deputies have insisted that Moscow destroy the missile. Instead, the government of President Vladimir V. Putin of Russia counteraccused the United States of violating the treaty’s terms because of the way in which it has deployed launchers for antiballistic missile systems in Europe.
“Countries must be held accountable when they break the rules,” Mr. Pompeo told journalists at the State Department.
“Russia has jeopardized the United States’ security interests,” Mr. Pompeo said, “and we can no longer be restricted by the treaty while Russia shamelessly violates it.”
But while the United States has insisted Russia’s actions sank the treaty, the Trump administration’s real aim is to broaden its prohibitions to include China.
Constrained by the treaty’s provisions, the United States has been prevented from deploying new weapons to counter China’s efforts to cement a dominant position in the Western Pacific and keep American aircraft carriers at bay. China was still a small and unsophisticated military power in the mid-1980s, and not a signatory to the treaty that was negotiated between the United States and a rapidly weakening Soviet Union.
By contrast, much of Beijing’s growing nuclear arsenal currently consists of missiles that fall into the distance ranges that are prohibited by the treaty that applies only to Russia and the United States.
“The issue now is whether the administration has a plan for what comes next,” said Pranay Vaddi, a fellow in the nuclear policy program at the Carnegie Endowment for International Peace and a former State Department official until 2017 who worked on nuclear arms control issues. “There is no question that the Russians committed a violation. But it is not militarily significant because it doesn’t change the balance of power in Europe.”
With the treaty on its last legs, the question is whether Mr. Pompeo’s announcement will result in a flurry of last-minute negotiations with Moscow — which seems unlikely — or whether it will accelerate the Cold War-like behavior among the United States, Russia and China.
Complicating that question is the American intelligence agencies’ warning this week that Russia and China are “more aligned than at any point since the mid-1950s.”
The fate of the treaty has quickly become a test of the continuing struggle inside the Trump administration, and with its allies, over how to handle an increasingly aggressive Russia.
Mr. Trump campaigned on remaking Washington’s relationship with Moscow; the open investigation by the Justice Department’s special counsel is, at its core, about whether he and his campaign aides promised to relieve sanctions and other impediments to Russia in return for financial or electoral benefits from Mr. Putin’s government.
But Mr. Trump has surrounded himself in the White House with hawkish advisers, including John R. Bolton, the national security adviser, who has been a major critic of treaties that he believes impinge the United States’ ability to counter new or rising foreign threats.
The decision to leave the nuclear arms treaty took American allies by surprise when word of the decision first leaked out in October and was quickly confirmed by Mr. Trump.
The North Atlantic Treaty Organization, the military alliance that was created to counter the Soviet threat 70 years ago, acknowledged that Russia had violated the I.N.F. treaty and called on Moscow in December “to return urgently to full and verifiable compliance.”
But the alliance stopped short of agreeing that the United States should withdraw, declaring then that the “allies are firmly committed to the preservation of effective international arms control, disarmament and nonproliferation.”
The announcement by Mr. Pompeo came just ahead of the expiration, on Saturday, of a 60-day deadline he gave Moscow to come into compliance with the treaty. He had no expectation that the Russians would heed his warning.
Mr. Pompeo’s formal announcement begins a six-month clock that Trump administration officials believe will end with a full American withdrawal from the treaty. Starting on Saturday, the United States would be free to begin to test or deploy its own weapons.
It is not clear whether that will happen; there are no weapons in the American arsenal that could be quickly deployed. That was the point of the treaty: It banned an entire category of weapons — land-based missiles with a range of 300 to 3,400 miles — that both the United States and the Soviet Union had deployed in the 1980s, and which at the time terrorized Europe.
Mr. Pompeo acknowledged a risk of a new arms race if the treaty is ultimately scrapped after the six-month window. “We hope they’ll come back into compliance,” he said of Russia.
He added: “There’s no mistaking that the Russians have chosen to not comply with this treaty and present the risk of continued arms growth in a way that they had committed to, back when they signed this treaty, that they would not do.”
For many years, the I.N.F. was considered a model arms control treaty. It allowed for on-site inspections and extensive exchanges of information — exactly what the Trump administration now seeks from North Korea and other states.
But in 2014, the Obama administration accused Russia of turning out a missile that violated the treaty, and last fall, Dan Coats, the national intelligence director, published a detailed history of the Russian violations.
Experts cited Russian unhappiness with the treaty, going back at least 10 years, before Moscow focused on new generations of missiles that would extend its reach without costing it much money. Russian officials have charged that American missile defense interceptors in Eastern Europe could be easily refashioned into offensive weapons, and that the rise of armed drones, which had not been invented when the treaty was signed, now threaten to provide the United States with similar intermediate-range ability without violating the precise wording of the treaty.
Ahead of Friday’s announcement, Russia had aggressively used social media accounts to portray the United States as the treaty-breaker and the aggressor. That argument has won some sympathy in Europe, where many critics portray the treaty’s demise as an example of the Trump administration putting its own agenda before Europe’s.
But the real action is likely to be in Asia. The Pentagon has already been developing nuclear weapons to match, and counter, what the Chinese have deployed.
Completing that effort would take years. Until then, officials said the United States is preparing to modify existing weapons, including its non-nuclear Tomahawk missiles, and is likely to deploy them in Guam, where the military maintains a large base and they would face little political opposition.