Every so often, critics of President Donald J. Trump wonder aloud and in print about the danger posed by putting nuclear weapons in the hands of a man who is so impulsive and vindictive. Those same fingers punching out storms on Twitter could, theoretically at least, press the button that brings on an apocalypse.

Because of a number of failsafes that prospect, for now, is remote. There is no threat that could prompt such an action, and not likely to be one. But Trump policy, deliberately and methodically, is laying the groundwork for a new arms race that will set the stage for greater nuclear tensions than we have seen since the height of the Cold War.

Having pledged in October to pull the United States out of a 1987 treaty limiting intermediate range nuclear missiles, Trump now has a new target in sight.

The New Strategic Arms Reduction Treaty is a 2011 accord between the United States and Russia that caps the two countries’ overall nuclear arsenals, including the most powerful intercontinental ballistic missiles and similar submarine-launched ballistic missiles.

New START is set to expire in February 2021 unless Washington and Moscow agree to extend it. But every expert The Daily Beast surveyed warned that Trump is likely to kill the treaty, either through quiet neglect or by declaring it un-American and refusing to negotiate its extension.

Ending the Intermediate-Range Nuclear Forces treaty would be bad, experts said. But ending New START could be catastrophic, they stressed.

“ Trump said he wanted to grow the U.S. atomic arsenal tenfold to the pre-treaty levels of the mid-1960s. In those years, the United States and Russia built new nukes at a rate of several per day. ”

“The collapse of the U.S.-Russia arms control architecture would mean Russian nuclear forces were unconstrained, our ability to verify what Russia is doing would be curtailed and the incentives to engage in costly nuclear competition would be magnified,” Kingston Reif, a policy director at the Arms Control Association in Washington, D.C., told The Daily Beast.

The State Department isn’t eager to discuss the treaty. “The U.S. government is currently considering its position on New START and discussing various possibilities,” Paul Harrison, a department spokesperson, told The Daily Beast. “It is important to resolve the INF issue first.” Russia has apparently violated some terms of the INF treaty by deploying a new type of shorter-range nuclear cruise missile.

New START is the latest in a long line of nuclear treaties dating to the late 1960s. Beginning with the Strategic Arms Limitations Treaty, which President Richard Nixon and Soviet leader Leonid Brezhnev signed in 1972, the United States and the USSR, later Russia, whittled down their respective nuclear arsenals from tens of thousands of warheads apiece to just 1,550 apiece under the terms of New START.

Equally importantly to the warhead caps, the treaty includes verification measures. U.S. and Russian inspectors have access to the other countries’ data and major nuclear-weapons sites.

“This is the most significant arms control agreement in nearly two decades, and it will make us safer and reduce our nuclear arsenals along with Russia,” President Barack Obama said in December 2010 after the Senate voted 71 to 26 to approve the treaty.

But the agreement has an expiration date: 2021, with an option for a five-year extension. And experts told The Daily Beast that Trump, with the strong encouragement of his extremist National Security Advisor John Bolton, probably won’t negotiate with Russia to extend New START.

“Left to his own devices, Trump would let it drift,” Jon Wolfsthal, a former nuclear adviser to Obama, told The Daily Beast. But Bolton “likes to rip up arms control deals.”

“He believes they constrain U.S. military options,” explained Michelle Dover, a nuclear expert with the San Francisco arms-control group Ploughshares Fund.

In 2010, Bolton—then with the American Enterprise Institute in Washington, D.C.—attacked New START as unilateral disarmament. “New START encumbers us with unnecessary constraints that will distort strategic priorities and weapons-development for decades,” Bolton wrote in The Wall Street Journal.

Trump, a self-styled artist of the deal, apparently has his own less ideological reasons for opposing the treaty.

During a phone call with Trump in January 2017, Russian president Vladimir Putin allegedly urged the American president to extend New START. But Trump reportedly brushed off Putin’s request, calling the treaty a “bad deal.”

In a July 2017 meeting with Pentagon officials, Trump reportedly said he wanted to grow the U.S. atomic arsenal tenfold to the pre-treaty levels of the mid-1960s. In those years, the United States and Russia built new nukes at a rate of several per day.

Trump’s broad antipathy toward Obama-era agreements dovetails with his apparent enthusiasm for more nukes. Trump has torn up practically all of Obama’s major treaties and international agreements, including the Paris climate-change accord and the Iran nuclear deal.

That gives Bolton leverage. “Bolton is taking advantage of Trump’s belief that treaties he didn’t negotiate inherently are bad deals,” Dover said.

But with his threat to pull the United States out of the INF Treaty and let New START die, Trump is attacking treaties with much deeper roots.

“He stabbed Reagan’s INF treaty in the back and I see nothing that will stop him from killing START in its sleep,” Joseph Cirincione, Ploughshares’ president, told The Daily Beast. “All he has to do is let it expire.”

While Bolton categorically rejects any self-imposed limits on U.S. military power, it’s possible Trump simply doesn’t fully understand or appreciate the true costs and benefits of New START and other arms-control agreements.

Beside lowering the risk of nuclear war, New START keeps down U.S. and Russian military costs and strengthens diplomatic ties between the atomic powers, experts said. “There’s really no strategic upside to terminating New START,” Hans Kristensen, a nuclear expert with the Washington, D.C.-based Federation of American Scientists, told The Daily Beast.

After adding tens of billions of dollars to the Pentagon’s budget in his first two years in office and also deeply cutting taxes—parallel moves that have resulted in skyrocketing federal budget deficits—Trump is asking for steep spending reductions starting next year.

There’s simply no money for a massive expansion of the U.S. nuclear arsenal, even if an expansion made sense. “It’s not like the U.S. is going to start drastically ratcheting up the number of its ICBMs [and submarine-launched ballistic missiles], even without a limit,” Kristensen said.

Russia likewise has been cutting, not growing, its own military spending. Moscow is enhancing its atomic arsenal, but not significantly expanding it.

Without a treaty, the United States and Russia might add a few new nukes. But the real problem is the end to mutual inspections—and the mistrust that might result. Washington and Moscow would have next to no idea what the other country was up to with regard to nukes. “We’d have no verification,” Kristensen said.

The build-up to the Iraq war of 2003 should have been an object lesson in the danger of what then-Defense Secretary Donald Rumsfeld called “unknown unknowns.” Ideologues make assumptions about weapons programs, and without any trustworthy inspections to determine the truth, the country can be stampeded toward war.

If Trump makes good on his threat to end both the INF Treaty and New START, it would be the first time since 1972 that the United States and Russia “have not been bound by a binding arms-control agreement,” a group of former high-level U.S. military officers warned in a letter to Trump dated Nov. 6.

It’s likely just one thing can save New START, Zak Brown, another Ploughshares nuclear expert, told The Daily Beast. “If the Dems take the White House in 2020, they’d likely race to get a New START extension by February 2021.”