And so Mr. Putin is turning to a familiar diversionary tactic — raising tensions to just below the boiling point with neighboring Ukraine and its pro-Western government. Since February, a cease-fire negotiated last summer has been shredded by Russian-backed forces in two eastern provinces they have partly controlled since 2014. A number of Ukrainian soldiers have been killed, including two this week. Meanwhile, Russia has sent thousands of regular troops to reinforce already-large deployments near the international border and in the Ukrainian province of Crimea, which Moscow claims to have annexed.
Mr. Putin has succeeded, at least, in getting the West’s attention. The U.S. European Command raised its alert level to “potential imminent crisis,” the highest level. In the past week, Ukrainian President Volodymyr Zelensky has received supportive phone calls from Mr. Biden, British Prime Minister Boris Johnson and NATO Secretary General Jens Stoltenberg. French President Emmanuel Macron and German Chancellor Angela Merkel raised Ukraine in a video call with Mr. Putin last week; the chairman of the Joint Chiefs of Staff, Gen. Mark A. Milley, meanwhile called his Russian counterpart. On Thursday, Ms. Merkel spoke to Mr. Putin again, telling him to reverse the military buildup.
Predictably, the Kremlin’s propaganda machine is portraying Ukraine as the aggressor and warning of a war that will “destroy Ukraine,” as Foreign Minister Sergei Lavrov put it. Both Russian and Ukrainian analysts are skeptical that Mr. Putin would launch an all-out assault; the sour mood of his citizens would not be improved by a stream of military casualties. But he may be looking to deliver a quick bloody nose to Ukrainian forces, following which he could demand that Mr. Zelensky deliver political concessions in exchange for a new cease-fire. He also may hope to undermine Mr. Biden’s effort to rebuild U.S.-European relations by exacerbating transatlantic differences over Ukraine.
Western governments will hope that their diplomatic flurry will deter Mr. Putin — but they must be prepared if it does not. The United States, which has helped Ukraine with military equipment and training, should be prepared to deliver further materiel if Ukrainian forces come under attack. And Western governments should have fresh sanctions ready: Among other things, any aggression should spell the end of the already controversial Nord Stream 2 gas pipeline between Russia and Germany. Mr. Putin must not be allowed to use war against Ukraine as a way to escape from his deepening domestic political trouble.