Vladimir Putin “made a tragic mistake,” by embarking on war with Ukraine, says Randall Stone.

At the same time, Stone, a political science professor and the chair of the political science department at the University of Rochester, stresses that the West must be careful to avoid escalation; in particular, NATO must not send air forces into Ukraine.

“It appears credible that Putin would be willing to escalate,” says Stone, an expert on Russian and Eastern European politics who serves as the director of the University of Rochester’s Skalny Center for Polish and Central European Studies. “Why? Because he was willing to take the risk of the invasion in the first place. He has chosen to put himself in a position where if we intervened, he loses, and probably loses everything, not just Ukraine, but his regime, maybe his life.”

Here, Stone explains the direction of the war in Ukraine, including the likelihood of Russia’s using biological, chemical, or nuclear weapons: