But the collapse of a major arms control treaty, signed by President Reagan and Soviet leader Mikhail Gorbachev in the final years of the Cold War, would signal a more serious and potentially dangerous breach between the nuclear-armed rivals.

In theory, letting the treaty terminate will allow Moscow to step up production of conventional and nuclear-tipped missiles that could threaten U.S. allies in Europe and elsewhere. For his part, Trump has complained the pact blocked the United States from developing or deploying new weapons.

Secretary of State Michael R. Pompeo acknowledged that Russian President Vladimir Putin is unlikely to change course and destroy the allegedly non-compliant missiles. A six-month countdown before either side can withdraw, required by the treaty, starts Saturday.

“When an agreement is so brazenly disregarded and our security is so openly threatened, we must respond,” Pompeo said at the State Department.

Trump’s decision had been expected and is consistent with his “America First” policies, which already saw Trump pull out of the Iran nuclear deal and the Paris climate accord. Trump’s national security advisor, John Bolton, is contemptuous of arms control agreements, which he believes tie U.S. hands.

Washington first accused Russia of violating the INF agreement in 2014, and has repeated the charge every year since. Trump warned in October that he would pull out if Russia didn’t comply.

Russia maintains it developed its cruise missile in response to the Pentagon’s growing capability to shoot down ballistic missiles. Washington says that effort is aimed at Iran and North Korea, but Moscow contends that the U.S. anti-missile program puts Russia at risk.

A U.S. missile defense site is operational in Romania while another is under construction in Poland.

Acting Defense Secretary Patrick Shanahan recently acknowledged that the expanding U.S. defenses were a major factor driving Russia and China to build faster and more survivable missiles.

“Frustrated by our mid-course defenses, they are aggressively pursuing new technologies to circumvent today’s systems,” Shanahan said in a Jan. 17 speech on the administration’s plans to expand missile defense.

Trump administration officials have expressed concern that China, which isn't a signatory to the treaty, is deploying short- and medium-range missiles in Asia that the U.S. can't directly counter because it is bound by the INF accord.

Pompeo and senior administration officials rejected critics’ claims that the White House is spurring a new arms race with Russia.

“If there is an arms race, it is Russia that started it,” said a White House official who briefed reporters on the condition of anonymity in keeping with administration rules.

The official did not answer questions about whether the United States will seek to develop and deploy new weapons overseas when the treaty terminates. “We are some time away to know what we want to deploy and where we want to deploy,” the official said.

The administration last year announced plans to develop a low-yield warhead for the Trident D-5 submarine-launched ballistic missile and a nuclear-armed, sea-launched cruise missile, calling those options “important for the preservation of credible deterrence against regional aggression.”

The Pentagon also could deploy a new ground-launched cruise missile or larger intermediate-range missiles. Some NATO allies are uneasy about keeping U.S. missiles capable of carrying nuclear warheads on their territory, although Poland may be willing to host U.S. missiles.

Andrea Thompson, undersecretary of State for arms control and international security, said the Trump administration has not held discussions with European allies about what will happen if the treaty terminates.

The INF treaty eliminated all nuclear and conventional missiles, as well as their launchers, with ranges of 310 to 620 miles, considered short-range, and 620 to 3,420 miles, or intermediate-range. It did not cover sea-launched missiles.

Arms control experts say the accord led to the destruction of 2,692 U.S. and Soviet missiles by 1991. The Arms Control Assn., a nonpartisan group in Washington, credits the treaty with helping end the Cold War.

"The only ones applauding the decision to tear up the INF treaty are the nuclear weapons manufacturers, eagerly anticipating the kickoff of Cold War II,” said Beatrice Fihn, executive director of the International Campaign to Abolish Nuclear Weapons, which was awarded the 2017 Nobel Peace Prize.

Joseph Cirincione, president of Ploughshares Fund, a Washington-based group that advocates for arms control, said walking away from even a flawed or violated treaty was senseless.

“When someone breaks the law, you don’t repeal the law,” he said. “Donald Trump walking out of Ronald Reagan’s treaty is a gift to Vladimir Putin. It doesn’t fix the problem. It makes it worse.”

Russian officials reacted angrily to Trump’s announcement Friday.

“The United States today took another step towards its destruction,” said Konstantin Kosachev, a Russian lawmaker and head of the upper house of parliament’s foreign affairs committee.

Russian Sen. Oleg Morozov warned of consequences for Europe if the treaty is canceled.

"It is important that the Europeans realize that now they will become a target for Russian missiles," Morozov said.

Thompson, the State Department official, said treaty talks last month in Geneva with Russia’s deputy foreign minister, Sergei Ryabkov, were “professional” but unproductive.

The talks focused on the cruise missile system that U.S. officials call the SSC-8 and Russians call Novator 9M729.

“We didn’t break any new ground. There was no new information,” Thompson told reporters at the Pentagon last week. “The Russians acknowledged having the [SSC-8] system but continued to say… it didn’t violate the INF treaty despite showing them, repeated times, the intelligence and information” gathered by the U.S. and its allies.

Russian officials displayed the missile at a press event in Moscow last month, saying it could only travel 298 miles, just under the treaty limits.

Thompson rejected those claims, saying the U.S. was confident in its assessment that the missile could travel well beyond the allowable limit.

“Arms control works when you can fully verify the compliance with it,” Thompson said. “The transparency measures they brought to the table wouldn’t have done so.”

Special correspondent Sabra Ayres in Moscow contributed to this report.

https://www.latimes.com/politics/la-na-pol-trump-nuclear-treaty-20190201-story.html