Party Polarization and Legislative Gridlock

This article investigates how parties affect legislative gridlock-the inability of government to enact significant proposals on the policy agenda. Conventional accounts suggest that divided party control of govemment causes such stalemate. I offer an alternative partisan model of gridlock that incorporates party polarization, party seat division, and the interaction between these two factors. Using an original data set of major legislative proposals considered between 1975 and 1994, I find that divided govemment does not affect gridlock once party polarization and party seat division are taken into account. Instead, I find that higher party polarization increases the likelihood of encountering gridlock on a given proposal, but that the magnitude of this increase diminishes to the extent that a party is close to having enough seats to thwart filibusters and vetoes.