Political theorists and empirical scholars have long assumed that democracy and participation are necessarily in tension. Partly for this reason, research on participatory democracy has focused on "mini-publics"-relatively small-scale and/or local practices. Through an exploration of Brazil's National Public Policy Conferences, we provide the first evidence that participatory governance practices can directly shape important national public policy outcomes at the national level. Our findings call into question the longstanding critique that participatory practices are impractical on a large scale and thus unimportant to the overall functioning and quality of democracy. We find that participatory practices can deepen democratic regimes by opening the doors for greater and more direct civil society input into the substantive content of national governance.