President Donald Trump announced the other day that the United States will abandon a treaty, originally signed with the Soviet Union, designed to prevent the deployment of the exact sort of missiles that scare the bejeezus out of world leaders.

Trump accused Russia of violating the Treaty for years at a campaign rally in Montana, saying he will “terminate the agreement.” Abandoning the treaty will allow the United States to develop and deploy its own short- and medium-range ballistic nuclear missiles, particularly in the Asia-Pacific region against China.

During the Cold War the United States fielded several short and medium range ballistic missiles against the Soviet Union. The nuclear-tipped missiles, based in Western Europe, Turkey, and Japan, were part of a broader policy of containing the Soviet Union and, failing that, providing battlefield commanders with nuclear arms to blunt Russian attacks.

While the United States saw the system as primarily defensive, the Soviets saw the system as part of a worldwide network of U.S. weapons poised for a surprise first strike.

The reasoning being that if the United States launched a nuclear missile from, say, Montana, the Russian military would have about 25 minutes or so to do something. But if a ballistic missile was launched from Germany, and it was pointed directly at Moscow?

That would give the receiving end barely any time to respond at all. Which means that short-range ballistic nukes would be, in the wrong hands, very enticing to use in a first strike. If you’re going to use nukes, the thinking goes, it helps if the other guy is too dead to use them back against you.

In the late 1970s, the Soviet Union fielded the . With a range of 3,100 miles, SS-20s based in western Russia could rain nuclear warheads on almost all of NATO—with the exception of the U.S. and Canada. In response the United States fielded the and the , deploying them in the UK, Belgium, Netherlands, Germany, and Italy.

The introduction of these new nuclear-tipped missiles turned the tables on the Soviets: while the SS-20 could reach most of NATO in a matter of minutes, it could not strike the continental United States. Soviet intelligence assessed that both the Pershing II and the Gryphon could strike Moscow, the former in . (That was not actually true—the Soviets incorrectly believed the Pentagon was deliberately understating the Pershing II’s range to make it appear less threatening.)

Understandably, a six-minute warning time was much too short for the Soviets to properly react to nuclear attack. The Soviet leadership, already was pushed to the bargaining table. In 1987, the U.S. and U.S.S.R. signed the Treaty Between the United States of America and the Union of Soviet Socialist Republics on the Elimination of Their Intermediate-Range and Shorter-Range Missiles, otherwise known as the much shorter .

The INF Treaty, contrary to its name, does not ban nuclear weapons. Instead it bans nuclear delivery systems, in almost all cases missiles, with ranges between 310 miles and 3,400 miles. This had the result of removing from Europe and Asia. Parties to the INF Treaty were obligated to destroy these missiles, SS-20, Gryphon, and Pershing II, within three years.

The INF Treaty was a major milestone in arms control, though it did have limitations. The INF Treaty left untouched nuclear artillery rounds and short range ballistic missiles such as the Soviet . As short range weapons, they had no first strike potential beyond the battlefield. The INF Treaty prohibited intermediate range ground launched ballistic and cruise missiles, but left air and sea-launched missiles alone. The treaty’s 3,400-mile limit meant intercontinental ballistic missiles, launched from silos and trains in both the U.S. and U.S.S.R., were untouched.

Still, it removed potential first strike weapons from both sides, making everyone breathe a little easier. After the collapse of the Soviet Union the Russian Federation, which inherited the lion’s share of the U.S.S.R.’s nukes, declared its intention to stick with the treaty.

Meanwhile, on the other side of the world, China was busily developing its own ballistic missile arsenal. China, lacking a modern bomber, decided to concentrate its efforts in developing short, medium, and eventually intermediate range missiles with conventional warheads. These missiles were useful in intimidating Taiwan and later threatening Japanese and U.S. bases in the Asia-Pacific.

China has even developed medium range ballistic missiles capable of attacking U.S. carriers, so-called anti-ship ballistic missiles like the . In any future regional war, any adversary of China’s can expect to have ballistic missiles with conventional warheads rain down across its territory. China’s current state of the art is the , which can hit U.S. military bases in Guam. A carrier-killing variant is reportedly under development.

Back to Europe. In 2014, the U.S. State Department alleged Russia had —but refused to say which missile it was. Outside observers speculated the mystery missile was a new cruise missile known to U.S. intelligence as the SSC-X-8, and to Russia as the —a guess that was eventually proven correct. Another new weapon the U.S. was about was the RS-26 “Rubezh” intercontinental ballistic missile, which was tested below the 3,400 mile limit. (The RS-26 has also been tested .) The Trump Administration confirmed 9M729 was the treaty buster in 2017.

All of that leads us to this weekend, when he was walking away from the INF Treaty. Abandoning the treaty will allow the United States to develop its own medium and intermediate range ballistic missiles—and arm them with nuclear weapons.

Back to Asia again. Chinese missile development wasn’t really a concern for the Pentagon for much of the post-Cold War period, but Beijing’s military expansion and the aggressiveness has the Pentagon planning for big power war in the Asia-Pacific again. Now, the Pentagon must grapple with the possibility that in the event of war, its bases in Japan, South Korea and Guam, and warships at sea could become targets of Chinese missiles. At the same time, the INF Treaty prevents the U.S. from fielding similar missiles.

On one hand, canceling the INF treaty will show the Russians that actions have consequences. Moscow has been developing the 9M729 for years and was well aware of U.S. objections. If the Washington’s allegations are true, Moscow either doesn’t care about the INF Treaty or it thought the U.S. would not respond. The U.S. called Russia’s bluff and is free to develop its own missiles—to be based in Europe and Asia.

On the other hand, canceling the INF Treaty means the U.S. is surrendering the legal and moral high ground. Washington could remain in the treaty—at little cost to its own security and the security of its allies—berating Russia in public at every opportunity about its failure to live up to a legal obligation. The United States arguably does not need land-based intermediate forces in Europe, having large numbers of submarines and bombers equipped with land attack cruise missiles. In both Europe and Asia there are few if any U.S. allies willing to accept new missiles, with only the U.S. territory of Guam—two thousand miles from the Asian mainland—a sure host in the entire Asia-Pacific region.

There’s another, far more dangerous problem with basing intermediate-range missiles in Asia. In the event of war, there will be a tremendous urge to strike military targets across mainland China with precision-guided weapons. An intermediate range conventional warhead launched from Guam could reach Beijing in just 15 minutes—far longer than an ICBM launched from silos in the United States.

In this scenario, Beijing is the new Moscow with the same worries. If China detected such warheads racing towards the mainland, would it wait to determine if the warheads were conventional or nuclear before retaliating? Chinese nuclear forces that could be triggered by incoming intermediate range ballistic missiles.

Russia’s violation of the INF Treaty is real and a serious problem. It is not, however, a problem that requires the U.S. to abrogate a treaty in order to respond. Even if Washington gave itself the latitude to develop new missiles, could it find bases for them as trust in the U.S. government overseas is at an all-time low? Could it use them in combat without triggering a nuclear war? Could it even afford them?

Leaving the treaty unnecessarily complicates an already complicated world and leaves the U.S. without moral leverage on the nuclear issue. The U.S.—and the world—will be worse off without the INF Treaty.