In Vladimir Putin’s warped imagination, the real adversary of the Russian-backed separatists in Ukraine is not that country’s army but NATO and the United States. This mistaken view—a product of Mr Putin’s paranoia and his belief that America habitually pulls the world’s strings—will become somewhat truer if Barack Obama decides to send weapons to Ukraine’s government, as some bigwigs in Washington are urging. Without such help, Ukraine’s troops may struggle to resist a renewed advance by the rebels, themselves bolstered by sophisticated Russian kit and personnel (which, ludicrously, Mr Putin still denies providing). Advocates of arming Ukraine say it would help deter further land-grabs by Russia’s proxies, and dissuade Mr Putin from similar adventurism in other former Soviet states. Sceptics fear it would lead to yet more bloodshed, fail to alter the conflict’s outcome—and set up a more direct and dangerous confrontation between Russia and the West.