The Russians likely cheated. The arms-control community blew the whistle. And now, much to the alarm of U.S. allies, the administration of U.S. President Donald Trump is ripping up a decades-old rulebook for nuclear weapons without offering anything to replace it.

Just another day in U.S. diplomacy. Just another withdrawal from a major international agreement that could weaken global nuclear security.

On Saturday, the six-month countdown starts for the demise of a Cold War-era deal that has for more than 30 years preserved arms control in Europe. Moscow may have started the row by launching a treaty-prohibited missile in 2014, but Washington's termination of the treaty plays a broader destabilizing role, analysts said.

That's because at its core, the 1987 Intermediate-Range Nuclear Forces Treaty signed by U.S. President Ronald Reagan and Soviet leader Mikhail Gorbachev isn't merely a bilateral agreement; it also contributes to the stability and security of European allies by banning missiles that could reach regional ports, airfields and capitals.

"We're now entering into the Wild West — whether it's of nuclear armaments or the international order," said Brett Bruen, who served as the White House director of global engagement from 2013 to 2015. "We've now increased the possibility for an arms race."

U.S. diplomacy was once widely seen as a dependable pillar of stability. Not so much these days, Bruen said.

"We're witnessing the end of the American era, where the United States is no longer going to honour its commitments. The Trump administration is saying, 'Any treaty that others aren't following, we won't either."

'Easy out'

Aside from the destabilizing consequences of a withdrawal from an arms-control agreement, ending any treaty in this manner potentially presents an "easy out" for other nations: Violate the terms, ignore the weight of the agreement, and void the pact, Bruen said.

This trend could undermine confidence in the U.S., eroding respect for other treaty obligations. Leaving the INF treaty is the latest in a broad pattern of U.S. disengagement from major international agreements.

Former White House director for global engagement Brett Bruen says Trump's move to leave the treaty increases 'the possibility for an arms race.' (CBC)

Last May, the Trump administration pulled the U.S. out of the Iran nuclear deal that was reached between Iran and six world powers. In the first year of his presidency, Trump signed an executive order to withdraw from the Trans-Pacific Partnership trade deal and abandoned the Paris climate accord.

Russia denies it violated the terms of the INF treaty, which bans the U.S. and the states of the former Soviet Union from using ground-launched ballistic or cruise missiles with a range of 500 to 5,500 kilometres. Most nuclear experts beg to differ.

In a press conference on Friday, U.S. Secretary of State Mike Pompeo laid out the White House's rationale for pulling out of the INF: "Russia has jeopardized United States security interests, and we can no longer be restricted by the treaty while Russia shamelessly violates it."

U.S. officials critical of the agreement have also cited the growing military menace of China, which is not bound by the constraints of the treaty.

Secretary of State Mike Pompeo announced Friday morning the U.S. government's intent to withdraw from the Intermediate-Range Nuclear Forces treaty, citing Russian non-compliance. (Andrew Harnik/Associated Press)

Neither of those reasons has convinced Richard Haass, president of the Council on Foreign Relations, a New York-based security think-tank. He slammed the U.S. withdrawal as "a cure worse than the diseases" of Russian non-compliance and China not being bound by the treaty's rules.

Risks of new missile competition

To walk away from the treaty now wouldn't just be counter-productive, it would be downright "self-defeating," said Kingston Reif, director for threat reduction policy at the Washington-based Arms Control Association. It could trigger a cascading effect of weakened arms-control agreements.

"It's an own goal," he said of the withdrawal decision. "It's not going to bring Russia back into compliance with the agreement, and it runs the risk of unleashing a new missile competition between the United States and Russia."

What's worrisome to nuclear non-proliferation experts is the lack of a backup plan if the INF collapses, as it almost certainly will.

Without the INF, within two years there will be no legally binding limits on the world's two largest nuclear arsenals for the first time since 1972. That's because the New START (Strategic Arms Reduction Treaty) is due to expire in 2021, and there's a real risk it won't be extended, owing partially to hawkish U.S. National Security Advisor John Bolton's opposition.

Even if the Trump administration intends to build its own intermediate-range missiles, it will have a tough time finding a place to deploy them, said Matt Korda, who worked at NATO headquarters in the arms control, disarmament and non-proliferation centre.

Russian President Vladimir Putin "has already explicitly threatened to target any European countries that host U.S. intermediate-range missiles on their soil," Korda wrote in an email.

Russia now has six months to fall back into compliance with the INF treaty. While NATO's secretary general said the organization "fully supports" the U.S. withdrawal, it also vowed to continue to work with Russia to keep the agreement intact.

At least with a treaty in place, Russia would ostensibly have something to comply with. If the U.S. walks away, Russia would be free to openly violate the agreement's terms and deploy these systems wherever it pleases.

"Russia at least had to maintain some semblance of plausible deniability they were not violating the treaty," said Abigail Stowe-Thurston, an expert on Russian affairs who researches nuclear non-proliferation at the Federation of American Scientists.

Having the U.S. tear up the treaty might instead benefit Moscow by shifting the blame to the U.S. for undermining the global order. Stowe-Thurston expects to see more narrative plays from the Kremlin to frame the U.S. as the party that walked away from the treaty, despite the Russians failing to live up to their own obligations.

That would be quite a political gift for Moscow, she said, seeing as "the party that should bear responsibility for its demise is Russia."