With his war going slowly, Vladimir Putin raises the nuclear stakes

AS VLADIMIR PUTIN declared war on Ukraine in the early hours of February 24th, he warned the West to stay out of it. “Whoever tries to hinder us… should know that Russia's response…will lead you to such consequences that you have never encountered in your history,” he said. It was interpreted as a barely veiled threat to use nuclear weapons. On February 27th, several days into his war, and without much to show for the fighting so far, Mr Putin removed the veil entirely.

At a televised meeting with Sergei Shoigu, his defence minister, who looked taken aback, and the chief of the general staff, General Valery Gerasimov, Mr Putin accused the West of “unfriendly economic actions”. He was referring to the heavy sanctions announced in recent days, which threaten to batter Russia’s economy, as well as “aggressive statements” about Russia. “Therefore I order the minister of defence and the chief of the general staff to transfer the deterrence forces…to a special mode of combat duty.” In effect, it suggests that Russian nuclear weapons are moving to higher readiness.

This does not mean Mr Putin is preparing a nuclear strike. “Announcing it means that it is primarily a political message designed to impress us,” says Bruno Tertrais, an expert on nuclear deterrence at the Foundation for Strategic Research, a think-tank in Paris. “If he was getting ready to use nuclear weapons he would not [say so first].” Mr Putin’s aim is probably to deter the West from offering further support to Ukraine, which has so far fiercely resisted Russian ground assaults on several targets including Kyiv, the capital, and on February 27th Kharkiv, the second-largest city.

In recent days that support has been increasing. On February 25th Britain held a conference with more than 25 countries, including America and Canada, at which they pledged to continue sending ammunition, anti-tank weapons and other arms to Ukraine. A day later even Germany, which had previously refused to send lethal aid, and had blocked German-made weapons from being sent by others, changed its mind.

It said it would send 1,000 anti-tank weapons and 500 Stinger shoulder-fired anti-aircraft missiles “as quickly as possible”. It also allowed the Netherlands and Estonia to send rocket-propelled grenade launchers and howitzers respectively. The next day it went even further, announcing a huge expansion in defence spending, with a special fund of €100bn ($112bn). In addition to stanching the flow of such things to Ukraine, Mr Putin may also hope to stamp out any Western debates over the idea of a no-fly zone over parts of Ukraine.

His threat amounts to releasing the safety catch on a firearm. The reference to “special mode of combat duty” probably refers to the command and control of Russian nuclear forces. In peacetime, the system is thought to be incapable of transmitting launch orders, as if its circuits are disconnected, says Pavel Podvig, an expert on Russian nuclear forces at the United Nations Institute for Disarmament Research, a think-tank in Geneva. In moments of crisis Russian officials can “bring the system into a working condition, connecting the wires”, says Mr Podvig, “so if a launch order is issued it can go through”.

Once that happens, he says, the system is designed to allow a launch to occur even if Mr Putin is incapacitated—though that requires detecting a nuclear detonation on Russian soil. In addition to all that, “combat duty” might also trigger other preparations, such as nuclear-armed submarines leaving port or weapons being loaded onto bombers—things that would be visible to America and its allies through satellites and other means.

Russia is estimated to have 1,588 deployed nuclear warheads and 2,889 in reserve (America has 1,644 and 1,964 respectively). Its “deterrence forces” are not just nuclear ones, though. Russia considers strategic deterrence to span nuclear and conventional forces, including missiles such as the ground-launched Iskander, sea-launched Kalibr and air-launched Kh-101 and Kinzhal. Some of these missiles are dual-capable, which means that they can carry both conventional and nuclear warheads. Many have been spotted in recent weeks. The Kinzhal was seen under a Russian warplane in Kaliningrad on February 8th and Iskanders are thought to have been used in the first wave of missile strikes on Ukraine.

Jens Stoltenberg, the secretary-general of NATO, said that Mr Putin’s move was “dangerous rhetoric”. The alliance includes three nuclear powers—America, Britain and France—although France does not participate in joint nuclear planning and its forces are not formally assigned to NATO. In addition to their strategic forces, America also deploys “non-strategic” (sometimes called tactical) nuclear weapons to Europe, which have lower explosive yields. These can be carried by Belgian, German, Italian, Dutch and Turkish jets, the idea being to ensure a wider range of allies have a stake in nuclear deterrence.

Western nuclear forces do not need to go on higher alert, Mr Tertrais thinks. “I see no reason for a tit-for-tat,” he says. “Quite the contrary: we must appear cool-headed and show that he [Mr Putin] is the one losing his temper.” But the risks of misperception and misunderstanding are higher in wartime, and Mr Putin’s willingness to gamble has been proven to be greater than many assumed. Jon Wolfsthal of Global Zero, an advocacy group, and a former arms-control official in the Obama administration, urges America’s chairman of the joint chiefs of staff, the country’s top military officer, to remain in regular contact with General Gerasimov—and to remind him, and his colleagues, that any resort to nuclear weapons “makes them personally accountable under the laws of war”.

Mr Putin himself seems accountable to no one. In the 1950s Thomas Schelling, an economist and nuclear strategist, pointed out that the most credible threats were not those that promised an action with certainty, but left something to chance. “The threat is not quite of the form ‘I may or may not, according as I choose,’” noted Schelling, “but…‘I may or may not, and even I can’t be altogether sure.’” Mr Putin has gambled heavily. Now he is raising the stakes.

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