In Latin America, the drafters of early nineteenth-century constitutions were skeptical of implementing republican forms of government. Uruguay was an exception. Under the Swiss-educated reformist José Batlle y Ordóñez (1904-07, 1911-15), the groundwork was set for a new constitution that would bring about a secular democratic republic. Indeed, the 1918 Constitution replaced a conservative and centralist constitutional system with a regime of participatory democracy. This article advances a new interpretation of Uruguay’s participatory democracy and argues that, despite the brief endurance of the 1918 Constitution, participatory democracy may be an effective mechanism for constitutional entrenchment where it helps to create popular support for the rule of law and institutional stability.