Russia’s invasion of Ukraine shows the limits of nuclear deterrence
Since Russia invaded Ukraine on February 24, Russian President Vladimir Putin has given orders to increase the alert level of Russia’s nuclear forces and has made veiled nuclear threats. The blatant aggression against Ukraine has shocked Europe and the world. The war is a tragedy for Ukraine. It also exposes the limits of the West’s reliance on nuclear deterrence. Deterrence refers to the idea that possessing nuclear weapons protects a nation from attack, through the threat of overwhelming retaliation. This concept is widely credited for helping prevent war between the United States and the Soviet Union during the Cold War. However, Russia’s invasion of Ukraine casts a harsh light on its downsides. Most obvious is that Putin is using nuclear deterrence not to protect Russia but rather to have his way in Ukraine. Russia’s nuclear weapons deter the West from intervening with conventional military forces to defend Ukraine. Despite scattered calls in the U.S. for the creation of a “no-fly zone” over some or all of Ukraine, the Biden administration has wisely resisted. In practice this would mean shooting down Russian planes. It could lead to World War III. On the other side of the ledger, NATO’s nuclear weapons presumably deter Russia from expanding the war to NATO countries, such as Poland, Romania or the Baltic states. Thus, the nuclear balance of terror likely deters a wider European war but leaves Ukraine to struggle on with only limited support and perhaps eventually to be swallowed. On balance, NATO states do not seem very reassured by their vaunted nuclear deterrence. They continue to worry about the (remote) possibility of a Russian conventional attack beyond Ukraine.
This is not the first time Putin has rattled the nuclear saber. He also did so in 2014 during Russia’s invasion of Crimea, when Russian leaders talked openly about putting nuclear weapons on alert. In 2015, Russia threatened Danish warships with nuclear weapons if Denmark joined NATO’s missile defense system. Putin likes to wave about his nuclear weapons as a reminder to the West (and perhaps to himself) that Russia is still a great power. In the current crisis, Putin clearly wants the US and NATO to know that if the West were to intervene with military force on behalf of Ukraine, he might reach for his so-called tactical (or “nonstrategic”) nuclear weapons.