The US "Nuclear Posture Review" published by the Pentagon late last week announced that the United States would be getting two new types of nuclear weapons to provide, in the words of US officials, "more flexible capabilities to give tailored deterrence".
"Tailored deterrence"? What on Earth is that supposed to mean?
It's a brand new euphemism that is designed to disguise an old, largely discredited and very dangerous concept. The United States is once again playing with the notion of a "limited" nuclear war – and everybody else is very unhappy about it.
Sergei Lavrov, the Russian Foreign Minister, called the move "confrontational", and expressed "deep disappointment". The Chinese defence ministry said: "We hope that the United States will abandon its Cold War mentality [and] earnestly assume its special disarmament responsibilities."
Even the Iranian Foreign Minister warned that the new move would bring the world "closer to annihilation".
What the United States is actually going to do is change some of its existing nuclear weapons so that they make a smaller explosion. It's also going to put nuclear-tipped cruise missiles back on some of the navy's ships. At first glance, this is not very exciting stuff, but it really is very foolish and quite dangerous.
The main reason the Nuclear Posture Review gives for the new weapons is that the US military are worried that other countries may see its existing nuclear weapons as too big to be used. So the Pentagon also wants lower-yield bombs and "low and slow" cruise missiles in order to convince everybody else that the US would actually use them.
Really? Do they really think that when those "revisionist powers" see the new, smaller American nukes (no bigger than the bomb that destroyed Hiroshima), they will say to themselves: "I never believed the Americans would use megaton-range thermonuclear weapons on us, but they might actually use piddling little atomic bombs, so I'd better not invade Lower Slobbovia after all."
Nonsense. The Pentagon pretends that the new nukes will just fill a gap under the deterrent fence so that "Russia understands that any use of nuclear weapons, however limited, is unacceptable". But what it is really after is a credible nuclear war-fighting capability.
This is the old fantasy that you can safely fight a limited nuclear war in some distant part of the world without risking major damage to the homeland.
It's a fantasy that has been killed many times, but it never stays dead for long. It just seems wrong and unnatural to the military mind that you should have these hugely powerful and expensive weapons and never be allowed to use them in any circumstances – that they exist entirely and exclusively to deter the other side from using its own nuclear weapons.
It's so frustrating that in every military generation there are people who spin theories about how you might safely fight a limited nuclear war.
The first time their ideas gained a temporary foothold in American strategic thinking was in the late 1950s, and they have resurfaced at least twice since then.
Here they come again — as predictable as the monsoon — and once again more sensible people will have to devote time and energy to defending the core concept of nuclear deterrence.
As Bernard Brodie, the father of the theory of nuclear deterrence, wrote in 1946: "Thus far the chief purpose of our military establishment has been to win wars. From now on its chief purpose must be to avert them. It can have almost no other useful purpose."
That is true, but it is not compatible with traditional military thinking, so limited nuclear wars that you could actually fight keep sneaking back on to the agenda, usually in disguise. The current proposal is not some transient whim of Donald Trump's. It has been gestating within the US military for some time.
It may be possible for the US military establishment to sell this really bad idea to the American media, the Congress and the White House, but do not imagine that the Russians or the Chinese are fooled. They know exactly what the Pentagon is up to, and they don't like it one bit.
In due course, they will respond, and the world will get a little more dangerous.
■ Gwynne Dyer is an independent journalist whose articles are published in 45 countries.