Russian cheating requires a strong response. “In the capitals of the North Atlantic Treaty Organization, there is a clear lack of confidence in the United States’ reliability as a military ally.”

Sound familiar? It’s from a report in The Times dated October 7, 1979. Donald Trump isn’t the first American president about whom U.S. allies took a decidedly skeptical view.

Back then, the question was whether, and how, Jimmy Carter would respond to the Soviet Union’s deployment of the SS-20, a medium-range nuclear missile that threatened military installations in Western Europe and against which the Atlantic alliance had no equivalent. Later that year, Carter agreed that the U.S. would deploy hundreds of intermediate-range Pershing II and cruise missiles to Europe in response, a policy the Reagan administration completed in the early 1980s.

The history is worth remembering now that the U.S. has formally exited the 1987 Intermediate Nuclear Forces (I.N.F.) treaty, following many years of cheating by Russia and failed diplomatic efforts to bring it into compliance. Moscow has secretly fielded an estimated 100 ground-launched cruise missiles “designed to target critical European military and economic infrastructure, and thereby be in position to coerce NATO allies,” according to Dan Coats, the former director of national intelligence. Russia is also believed to be violating the 1996 Comprehensive Nuclear Test Ban Treaty.

This is happening while the U.S. is being challenged on multiple nuclear fronts. China is modernizing its nuclear forces and is expected to double its nuclear stockpile within a decade, according to the Defense Intelligence Agency. North Korea continues to test missiles and shows no signs of wanting to relinquish its bombs as part of a deal with Trump. Pakistan is rapidly expanding its arsenal, increasing the possibility that a warhead could fall into terrorist hands. And Iran’s resumption of nuclear work, a massive threat in its own right, tempts its regional rivals to follow suit.

What to do?

The standard answer is more arms control. Some have argued that the U.S. should continue to honor the I.N.F. treaty irrespective of Russian violations. In the current issue of Foreign Affairs, former Senator Sam Nunn of Georgia and former Energy Secretary Ernest Moniz, both Democrats, warn of the “toxic mix of decaying arms control and new advanced weaponry,” and argue against the forward deployment of nuclear weapons. The liberal answer to the Iran crisis is to ret urn to Barack Obama’s nuclear deal.

But the problem with all arms-control treaties isn’t that they lack for good intentions. It’s that the bad guys cheat, the good guys don’t, and the world often finds out too late.

Germany cheated on the arms limitations imposed by the Versailles Treaty. The Soviet Union cheated on virtually all of its international accords, including the 1963 Limited Test Ban Treaty and the 1972 Antiballistic Missile Treaty. North Korea cheated on the 1994 Agreed Framework with the Clinton administration. Iran repeatedly violated its commitments under both the Nonproliferation Treaty and the Iran deal itself.

And now Russia is cheating again.

As in the late 1970s, the immediate risk is that Moscow could threaten a NATO ally in a way that gives the U.S. no proportionate response — only capitulation or escalation. This ought to especially alarm Trump critics (including me) who think he’s been dangerously ambivalent about U.S. security guarantees to exposed allies like Estonia.

That same risk applies in East Asia. The Trump administration appears to be holding up an $8 billion sale of F-16s to Taiwan, likely as a bargaining chip in trade negotiations with Beijing. But that can only further convince Chinese military planners that the U.S. has neither the political will nor adequate military means to help defend Taiwan in the event of an attack or invasion from the mainland.

The reunification of China by force would expose all U.S. security assurances as dubious, if not downright worthless. It would be an invitation to aggression by other revisionist powers in other theaters. It would also serve notice to countries like Japan, South Korea and Saudi Arabia to obtain nuclear arsenals of their own. Those who dislike nuclear weapons in the hands of the United States will dislike them even more in the hands of such states.

Hence the logic of U.S. nuclear deterrence, including the “extended deterrence” Republican and Democratic administrations furnished our allies for over 70 years. But that logic depends on maintaining a large, modern and calibrated arsenal that contains no gaps in a potential escalation cycle. Right now, the U.S. arsenal does have gaps, thanks to Russian treaty violations, is increasingly decrepit, thanks to delayed modernization, and may not be large enough in the face of not one, but two, major nuclear adversaries.

I began this column with Jimmy Carter to make two simple points: The U.S. has surmounted similar challenges before, and liberal presidents have understood the need for a wide range of nuclear weapons. I’ll add a third: It was Carter’s tough decision to field the missiles to Europe, more than Reagan’s lauded decision to remove them, that did more to win the Cold War.

Bret L. Stephens has been an Opinion columnist with The Times since April 2017. He won a Pulitzer Prize for commentary at The Wall Street Journal in 2013 and was previously editor in chief of The Jerusalem Post. @BretStephensNYT • Facebook