Recent reports of a Defense Science Board study advocating the development of low-yield nuclear weapons sets to life yet another round of discussion about deterrence and nuclear modernization.

Deterrence theory says that the other side doesn’t launch an attack on you because they know that the counterattack that you would launch would wipe them off the planet (and in some conflicts destroy the planet). If one side instigates a nuclear armed conflict, they should expect the other side not to surrender as the Japanese did in World War II, but to unleash a volley of nuclear weapons back at the attacker, most likely launched from mobile launchers or submarines that survived the first attack. And the result was a vast radioactive wasteland where no one survived except the cockroaches. This is what people mean by an existential threat. For a good depiction of this, watch the now classic 1983 movie War Games.

The threat of Mutually Assured Destruction hung over relations between the US and the Soviet Union through most of the Cold War.  For you post-millennials, this is a larger version of the country we now refer to as Russia, and will refer to it this way going forward. To continue to be able to assert Mutually Assured Destruction the US and the Russians built ever larger arsenals with ever larger yields. Mutually Assured Destruction is also the reason why the Baby Boomers and Gen Xers spent their childhoods doing duck and cover drills because if the Russians launched an attack on the US, your plywood desk would totally protect you. The underlying premise of this theory was, “Don’t start something, won’t be nothing.”

But some people didn’t like some of the side effects of these ever-larger arsenals and Mutually Assured Destruction. They argued that the US nuclear arsenal has weapons with such a big yield that the US is afraid to use them because we are afraid of the conflict escalating in a way that destroys the entire planet. They argue that the Russians and the rest of the world knows that we don’t want to use the nuclear weapons because they are so destructive, so our adversaries don’t take our threat seriously and are therefore not deterred.

People have long argued that the US should develop low-yield nuclear weapons so that they will be easier to use, and therefore people would take our deterrence threat more seriously. During the Cold War, the US developed backpack sized nuclear weapons. They were phased out after the fall of the Soviet Union, but the Bush Administration pushed this line of argument forward in 2003 when it tried to fund a $6 million study into low-yield nuclear weapons, when they were vigorously opposed by Senators Kennedy and Feinstein, who ultimately prevailed. Kennedy and Feinstein argued that making nuclear weapons smaller and more usable would make it more likely that you would actually use them. Thus, by making nuclear weapons smaller, you would make nuclear war (and its inevitable escalation through the larger yield nuclear weapons) more likely. Thus, mini-nukes would be a gateway drug to a full-fledged nuclear war.

During the Obama administration, this debate over small nuclear weapons was largely dormant, but toward the end of the Obama Administration the proponents of low-yield nuclear weapons came back, like zombies arising from the grave. The current nuclear weapons arsenal is quite old, and coming to the end of its service life. Over the next few years, the Administration and Congress are going to have to decide how to proceed over a very expensive and costly modernization. Indeed, President Trump has directed a review to looking at modernizing the nuclear weapons arsenal in his executive order on defense spending.

So, to recap, we have a President who wants to review nuclear modernization. We have a Defense Science Board report that is recommending that the US wants to make nuclear weapons smaller and therefore more useable. During the campaign it was reported that Trump repeatedly asked his advisors, “If we have them, why can’t we use them?” And we currently have a President acts rashly with a disregard for the consequences and without seeking the advice of the national security professionals around him.

Given all that, is it any wonder that some members of Congress want to prohibit the President from firing the first nuclear shot without a Congressional declaration of war?

Image: An M-388 Davy Crockett nuclear weapon mounted to a recoilless rifle on a tripod, shown here at the Aberdeen Proving Ground in Maryland in March 1961. It used the smallest nuclear warhead ever developed by the United States. Via US Dept. of Defense.