Very soon, Congress will have to make a major decision: should it approve the Trump administration’s request for new, smaller, more usable nuclear weapons?

No, it should not. There is no need for such weapons, and building them would make us less safe. These so-called “low-yield” nuclear weapons are a gateway to a nuclear catastrophe.

There is a false narrative in Washington that the United States has a “gap” in its ability to deter the use of nuclear weapons by Russia. Administration officials allege that Moscow believes that an American president would not respond to Russian use of “tactical,” or lower-yield, nuclear weapons since his only options include “strategic,” or high-yield, ones. Since our president would not want to start an all-out nuclear war, he would be “self-deterred” from using big nukes, the logic goes, and Moscow would have a path to using small nukes that we could not block.

Thus, to plug this so-called “deterrence gap,” the Trump administration wants new low-yield nuclear weapons, which it would place alongside much larger warheads atop the Trident missiles of Ohio-class submarines.

Congress has stopped similar misguided efforts in the past, on a bipartisan basis. In 2005, lawmakers rejected a Bush administration plan for a new “low-yield” nuclear bomb called the “nuclear earth penetrator.” The next year, Congress killed another plan to mix different warheads on Trident missiles.

As Rep. David Hobson, R-Ohio, said at the time, “What worries me about the nuclear penetrator is that some idiot might try to use it.”

Indeed, the greatest concern about the proposed low-yield Trident warhead is that the president might feel less restrained from using it in a crisis. That is a greater danger than the possibility that he might feel “self-deterred” from using bigger nuclear weapons. When it comes to using a nuclear bomb, restraint is a good thing.

The administration’s justification for new low-yield Trident warheads fails on many levels, including these:

1. There is no “deterrence gap.” The United States has a massive nuclear arsenal of almost 4,000 warheads, half of which are deployed on land-based missiles, submarines, and bombers. The administration is rebuilding this arsenal at an estimated cost of $1.7 trillion, with inflation, over the next 30 years. One can certainly argue (as we have) that this massive program is excessive, is fueling a new arms race with Russia, and should be scaled back. But there can be no doubt in Russia’s mind that the U.S. is serious about maintaining an unambiguously strong nuclear deterrent.

2. We already have low-yield nukes. As part of that massive arsenal, the United States already has about 1,000 low-yield atomic weapons, including gravity bombs and cruise missiles, both of which are being modernized at great expense. If the president really ever needed to use a low-yield nuke, he has plenty.

3. Nuclear war cannot be controlled. Perhaps the biggest fallacy in the whole argument is the mistaken and dangerous belief that a “small” nuclear war would somehow stay small. That if Russia used a “low-yield” nuclear weapon, the U.S. would respond in kind, and that things could stay at that level. There is, of course, no experience to support this dubious theory.

But we came close during the Cuban missile crisis. There, in addition to the known but not-yet-operational medium-range missiles, the Soviets had deployed tactical (short-range) nuclear missiles that were already operational—with launch authority delegated to the unit commander—and we had no idea they were there. If President Kennedy had followed the unanimous recommendations of his Joint Chiefs, he would have invaded Cuba, where our troops would have been decimated on the beachhead by those tactical nukes. Would this nuclear war have stayed “small”? Hardly. There can be little doubt that tactical use would have precipitated a general nuclear war.

Analysts, sitting at their desks, write about “escalation control,” but the reality is that in a real war the analysts would not be making the decisions. Indeed, it is unlikely that the president would have full control over all decisions on weapons use. In the heat and fog of war, decisions tend to be made by the commanders doing the fighting, dealing with the tactical situation as it evolves and using the weapons they have to their best advantage.

Fundamentally, it is unlikely that there is such a thing as a limited nuclear war, and preparing for one is folly. "A nuclear weapon is a nuclear weapon," said George Shultz, who served as President Ronald Reagan's top diplomat. “You use a small one, then you go to a bigger one. I think nuclear weapons are nuclear weapons and we need to draw the line there.” Defense Secretary Jim Mattis said recently, “I don’t think there’s any such thing as a tactical nuclear weapon. Any nuclear weapon used at any time is a strategic game changer.”

The Trump administration is asking Congress for about $88 million for this new low-yield Trident warhead. This new warhead is dangerous, unjustified, and redundant. Congress has the power to stop the administration from starting down this slippery slope to nuclear war. There has never been a better time to exercise that authority.