The president is reluctant to send more aid to Ukraine, let alone U.S. troops; nor does he want Ukraine admitted to NATO. As for overseeing an eventual ceasefire and guaranteeing Ukraine’s security — without which an armistice would be meaningless, given Moscow’s neo-imperialist ambitions — he sees that as Europe’s problem.

Easing sanctions won’t bring Russia’s president to the negotiating table. Only the knowledge he can’t win will force his hand.