The Expected Effects of Parties on Legislative Outcomes

Abstract

Part III focuses on exploring whether parties affect legislative outcomes despite chaos. Describing the legislative role of parties has been difficult even in non-chaotic legislatures. Krehbiel (Br J Polit Sci 23:235–266, 1993) and Cox and McCubbins (Legislative Leviathan. University of California Press, 1993) famously questioned the relevance of parties because he argued that the only thing that matters for explaining unidimensional outcomes is the ideological position of the median legislator-precluding the need for parties. In contrast, Cox and McCubbins (Legislative Leviathan. University of California Press, 1993; Setting the agenda: responsible party government in the US house of representatives, 2005) argued that while legislators had unidimensional preferences that tend toward median outcomes, political parties are able to use agenda-setting powers to move outcomes away from the median of the floor and toward the median of the majority party. Aldrich, Berger, and Rohde (2007) argued that parties are only able to concentrate powers if (1) parties are homogeneous internally, and (2) if they are polarized between each other. Finally, Shepsle and Weingast (1981) proposed that legislators have multidimensional preferences, and that legislative stability is only possible when agenda-setting rules create non-partisan outcomes. However, given my findings in Parts I and II, in order to explain partisan outcomes in Paraguay we would need to develop a new multidimensional and partisan theory of legislative outcomes that does not rely on agenda-setting powers to function.