This chapter rejects the ‘extrinsic’ view of public reason examined in Chapter 4, and argues that political parties can play an important role in helping citizens to relate their comprehensive doctrines to political liberal values and institutions. Once we understand the distinctive normative demands of partisanship, this chapter claims, we can see that there is no inherent tension between them and the demands of the Rawlsian overlapping consensus. This is because partisanship (unlike factionalism) involves a commitment to the common good rather than the sole advancement of merely partial interests, and this implies a commitment to public reasoning. The chapter further examines three distinctive empirical features of parties that particularly enable them to contribute to an overlapping consensus. These are their linkage function, their advancement of broad multi-issue political platforms, and their creative agency.