Political sociologists often assume that widespread grievances require a long legacy of intergroup oppression. Yet in nineteenth-century Uruguay, supporters of the White and Red political parties developed intense grievances against each other even though a legacy of oppression was missing. For explaining this puzzle I present an alternative perspective. It states that grievances first originate among political elites, which mobilize the masses through selective incentives in order to impose their will. If elites and masses are bound by close ties, sustained mobilization facilitates cross-class group identification and allows grievances to “trickle down” from the top to the bottom of the social structure.