A few more months without meaningful Western help and Ukraine will have lost the fighting core of its army — and its infatuation with the West. This will be replaced by a sense of betrayal, and there will be no way for Ukraine’s pro-European liberals to survive the backlash. The far-right extremists now on the fringe will ride into Kiev’s parliament on the lids of the caskets being shipped back from the front. Ukraine will become a ravaged conflict zone: a European Syria, or a hideously enlarged Bosnia.

We cannot let this happen. If we believe that Ukraine will one day become a member of the European Union and NATO, then we should be ready to arm it. We must face the fact that the costs of unlimited European Union and NATO expansion have meant war with Russia by proxy — and then fight the war. Having reignited the hottest moments of the Cold War, we must deal with the consequences of encouraging democratization in Eastern Europe.

This logic demands that we send Western military advisers to Kiev, and give the Ukrainians full intelligence and satellite support. And we must ship them guns, tanks, drones and medical kits by the ton. We must even be ready to deploy NATO troops if Russian tanks roll toward Crimea, as many fear they will, to build a land bridge to the mainland of southern Russia.