THE NAME of the weapon, designed in the late 1980s, was both an acronym—Army Tactical Missile System (ATACMS)—and, when said aloud, an exhortation—“attack ’ems”. But Ukraine could not, in fact, attack ’em—at least not inside Russia, not until November 17th, when it became clear that Joe Biden, America’s president, had changed course and given Ukraine permission to fire the longer-range missiles onto Russian soil. The decision will not dramatically change Ukraine’s flagging fortunes on the front lines, though it will boost morale and strengthen the country’s hand ahead of negotiations likely to be pursued by Donald Trump after January 20th. Until then, a tumultuous two months lie ahead.