The peril of inaction

IN A war as ugly as the one in Syria, several bleak lessons stand out: the longer it goes on, the bloodier it gets, the more countries are sucked into the vortex and the more unpalatable become the options to stop, or at least contain, the fighting. But perhaps the biggest lesson is how America’s absence creates a vacuum that is filled by dangerous forces: jihadists, Shia militias and now an emboldened Russia.Syria is a nasty complex of wars within a war: an uprising against dictatorship; a sectarian battle between Sunnis and Alawites (and their Shia allies); an internecine struggle among Sunni Arabs; a Kurdish quest for a homeland; a regional proxy war pitting Saudi Arabia and Turkey against Iran; and a geopolitical contest between a timid America and a resurgent Russia.