Putin has been winning in Ukraine. The country is nowhere near joining NATO, a western goal only a few years ago, and Russia’s annexation of Crimea is a geopolitical fact. Putin is also a master in using military force in ways that don’t quite cross over to hot war. Western powers have been signalling that they won’t allow a new invasion of Ukraine to go unpunished. But judging when to act, and how, is crucial. The pompous, yet vacuous rhetoric used by the west risks pushing the conflict over the line into a military one, for which there is no strategy or exit plan, writes Hew Strachan.