Those who prematurely proclaim Ukrainian victory seem to forget that the worse things go for Russia in conventional warfare, the higher the probability rises that Putin uses chemical weapons or a small nuclear weapon. Remember: His goal since 2014 has been to prevent Ukraine becoming a stable Western-oriented democracy integrated into Western institutions such as the North Atlantic Treaty Organization and the European Union. With every passing day of death, destruction and displacement, he may believe he is achieving that goal: rather a desolate charnel house than a free Ukraine.

More importantly, if he believes the U.S. and its allies aim to overthrow him — and if Ukraine continues to attack targets inside Russia, as it apparently did for the first time on Thursday night — he seems much more likely to escalate the conflict than meekly to resign the Russian presidency.

Those who dismiss the risk of World War III overlook this stark reality. In the Cold War, it was NATO that could not hope to win a conventional war with the Soviet Union. That was why it had tactical nuclear weapons ready to launch against the Red Army if it marched into Western Europe. Today Russia would stand no chance in a conventional war with NATO. That is why Putin has tactical nuclear weapons ready to launch in response to a Western attack on Russia. And the Kremlin has already made the argument that such an attack is underway.