The question we posed at the outset is whether bipartisanship or politics hold as appropriate explanations of congressional-executive relations in the historical periods to which they are typically applied, namely, the pre-Vietnam period in the case of bipartisanship, and the post-Vietnam period in the case of politics. The evidence suggests, first, that the bipartisan perspective applies best to the first two decades of the postwar era, but that it has not been replaced by the political perspective, in which partisanship and ideology are central concepts. Instead, the political perspective applies throughout the postwar era, even though it may now appear more pronounced because its most visible aspects are no longer overlaid by what is typically thought to be the moderating influence of bipartisanship. In this sense the two viewpoints are appropriately seen not as competing but as distinctly separate perspectives on the politics of policy-making that coexist simultaneously.