VLADIMIR Putin’s illegal annexation of four regions of Ukraine, which he claims are now to be regarded as part of Russia, represents a major escalation of the war he launched in February. The parallels with Hitler’s expansion strategy are growing stronger by the day. In the face of advancing Ukrainian forces, Russia’s president orders his forces to fire missiles and artillery indiscriminately at civilian populations. Wherever his troops are pushed back, further evidence of war crimes and mass murder is found.

And yet in some quarters of Europe, the desire to give Putin at least part of what he wants remains, on the assumption that he would then stop and economic relations could return to some semblance of what they were before. At least in private conversations, leading German industrialists argue for Munich-type appeasement. But Neville Chamberlain’s conciliation did not stop Hitler, and a similar approach will not stop Putin, who has designs on the Baltic countries, Poland, and probably others.

Fortunately, there is a better way: A major push by the European Union into energy conservation and renewables, coupled with a tight price cap on Russian oil and coal exports, and a willingness to lower that cap every time Putin escalates further.