Perhaps Mr Putin is planning a full-scale invasion, with Russian forces thrusting deep into Ukraine to seize the capital, Kyiv, and overthrow the government. Or he may seek to annex more territory in eastern Ukraine, carving out a corridor linking Russia with Crimea, the Ukrainian peninsula Mr Putin grabbed in 2014. Then again, he may want a small war, in which Russia “saves” Kremlin-backed separatists in Donbas, an eastern region of Ukraine, from supposed Ukrainian atrocities—and, at the same time, degrades Ukraine’s armed forces.