What is a tactical nuclear weapon?

Can Putin really use them in Ukraine, or are they just an empty threat?

This 155 howitzer round was America’s smallest tactical nuclear weapon.

In mil-speak, they are known as “tac-nukes,” and the first thing you need to know about them is that tactical nuclear weapons have been retired from our arsenal since 1992, although there are some reports that the U.S. maintains about 250 of its larger weapons as part of its NATO emergency response forces, the command and control of which can be more closely held. 

Going back to the 50’s and 60’s, we had tactical nukes in many forms:  as warheads on Corporal and Honest John missiles atop launchers which could be mounted on trucks and easily moved around the battlefield.  During one Armed Forces Day in Germany in 1956, when the Army put its weapons on display and you were allowed to climb onto tanks and pretend you were driving or shooting them, I remember seeing a weapon they called “the atomic cannon,” a 280 mm cannon towed by tractors on either end of a flatbed that resembled the extra-long “hook and ladder” firetrucks which could be steered from the front and back.  It was a ridiculous weapon with a 15 kiloton (kt) warhead that the thing could shoot only 7 miles.  It was tested only once at the military’s Nevada test site and was of course never used in Europe or anywhere else.

We eventually reduced our tactical nuclear warheads to a size that they could be fired by 8-inch and 155 mm howitzers.  These were deployed in Europe during the Cold War and were also never used.  All these tactical nuclear weapons and others were retired from service and disassembled at the direction of President George H.W. Bush at the end of the Cold War in 1991.

Post-Soviet Russia committed to do the same.  They didn’t.

Estimates of Russia’s stockpile of tactical nuclear weapons today vary wildly, from 1,000 to 2,000, estimated in recent news reports, to 5,000, a number reported by Pravda.ru in 2014: “Russia, according to conservative estimates, has 5,000 pieces of different classes of TNW [tactical nuclear weapons] - from Iskander warheads to torpedo, aerial and artillery warheads!”