In a lengthy piece published earlier this week, Vox media journalist Max Fisher details how a conflict between the US and Russia could spiral into a nuclear war. As with all Vox content, it has pop-art, like this 'choose your own adventure' World War III flow-chart.

Fisher does brush over a few things. He says Cold War leaders considered limited nuclear war, in which tactical nuclear warheads would be used on the battlefield rather than 'strategically' against population centers and cities, as 'unthinkable' and that they thought this type of conflict was not survivable or winnable. Not all Cold War leaders thought this, and there were significant debates throughout the period about escalation control and different theories about how each side would interpret the use of a nuclear weapon on the battlefield.

But incidents like the close call during the Cuban Missile Crisis, when a Soviet nuclear torpedo was almost fired at a US aircraft carrier, eventually proved to many the need for limits on tactical nuclear weapons. By the end of the Cold War, there was consensus that tactical weapons were inherently destabilising, and this led in part the Intermediate-Range Nuclear Forces (INF) Treaty in 1987.

But the INF Treaty did not cover all types of tactical nuclear warheads, merely their launchers. In fact, the 180 US nuclear weapons that are still deployed to bases in Belgium, Germany, Italy, the Netherlands and Turkey are hold-overs from this era of strategic thinking. These weapons are 'variable yield' models. Their destructive capacity can be changed for tactical and strategic purposes, depending on their intended use. These nukes, and their predecessors, were intended to be used against superior Soviet conventional forces in Europe by NATO in the event of a conventional war. Now, they act more or less as a physical guarantee of US extended nuclear deterrence to Europe.

What's really important about Fisher's article is his call for attention on the growing danger of Russian nuclear doctrine. Sometimes strategic thinking is more dangerous than the capabilities themselves, and in this case, the destabilising nuclear strategic thinking that characterised the early Cold War have returned to Putin's Russia (some strategists in Washington are also beginning to advocate for investment in more tactical nuclear weapons in the face of Russia's policy in Crimea and Ukraine).

First, Fisher argues that the mood in Moscow has substantially changed. He cites Russian strategic analyst Fyodor Lukyanov:

'The perception is that somebody would try to undermine Russia as a country that opposes the United States, and then we will need to defend ourselves by military means,' he explained. Such fears, vague but existential, are everywhere in Moscow. Even liberal opposition leaders I met with, pro-Western types who oppose Putin, expressed fears that the US posed an imminent threat to Russia's security.

Essentially, to reinforce Russia's growing strategic interests and to compensate for its substantial asymmetric disadvantage in conventional military means vis-a-vis the West, Putin has begun to reinvest in short- and medium-range nuclear-capable missiles, as well as lowering the threshold for potential nuclear use. A good example is the Russian ambassador to Denmark's comments earlier this year that if Denmark were to integrate into NATO's missile defence shield, Danish warships would then be targeted by Russian nuclear weapons. Here's Fisher on Russia's nuclear compensation:

 To solve the problem of Russia's conventional military weakness, he has dramatically lowered the threshold for when he would use nuclear weapons, hoping to terrify the West such that it will bend to avoid conflict. In public speeches, over and over, he references those weapons and his willingness to use them. He has enshrined, in Russia's official nuclear doctrine, a dangerous idea no Soviet leader ever adopted: that a nuclear war could be winnable.

The real danger of this shift is the idea of a 'de-escalation' strike, which has now been incorporated into Russian nuclear doctrine:

That corollary is Russia's embrace of what it calls a "de-escalation" nuclear strike. Go back to the scenario spelled out in Russia's military doctrine: a conventional military conflict that poses an existential threat to the country. The doctrine calls for Russia to respond with a nuclear strike. But imagine you're a Russian leader: How do you drop a nuclear bomb on NATO's troops without forcing the US to respond with a nuclear strike in kind, setting off a tit-for-tat cycle of escalation that would end in total nuclear war and global devastation?...

...Russia's answer, in the case of such a conflict, is to drop a single nuclear weapon — one from the family of smaller, battlefield-use nukes known as "tactical" weapons, rather than from the larger, city-destroying "strategic" nuclear weapons. The idea is that such a strike would signal Russia's willingness to use nuclear weapons, and would force the enemy to immediately end the fight rather than risk further nuclear destruction...

..."Such a threat is envisioned as deterring the United States and its allies from involvement in conflicts in which Russia has an important stake, and in this sense is essentially defensive," Sokov wrote. "Yet, to be effective, such a threat also must be credible. To that end, all large-scale military exercises that Russia conducted beginning in 2000 featured simulations of limited nuclear strikes."

Tactical nuclear weapons, particularly when paired with a doctrine that calls for their use in a seemingly oxymornic 'de-escalatory' fashion, are dangerous. Since the end of the Cold War, this is something analysts have mostly worried about in the South Asian context. The fact that this thinking has re-entered the world's most important nuclear relationship, that between the US and Russia, is an alarming step backwards.

Photo courtesy of Flickr user Megan Eaves.