A spatial theory of unified and divided government yields comparative statements about gridlock—the tendency of policies to remain unchanged in specified governmental and partisan regimes. An application of the theory to recent political history yields the prediction that the Clinton Administration’s prospects for breaking s-called partisan gridlock are bleak. Under either of two assumptions about party strength, gridlock is shown to be an invevitable theoretical by-product of heterogeneity of legislative preferences and super-majoritarian legislative and executive institutions. The institutional features in the analysis are the president’s constitutional right to veto and a Senate minority’s right to engage in “extended debate” (i.e., to participate in filibusters). Under specified conditions, each of these inhibits the otherwise-impressive convergence of public policies to the legislative median position. In addition to the broad prediction of unified gridlock, a more specific empirical test is outlined.