Where Do Agendas Come From?

Brendan Nyhan counters Matt Bai:

What Bai doesn't seem to realize is that elections do not ever indicate the will of the people in some well-defined sense (there is a vast technical literature on this point). The best political science research to date convincingly argues that mandates should be viewed as a social construction. Moreover, it's not clear that presidents enact legislation intended to make them more popular. Contemporary presidents tend to pursue the agenda of their party, not the median voter. Finally, the public mood tends to shift in the opposite direction of the party in power. For all of these reasons, the appealing notion that presidential candidates will propose an agenda, enact that agenda in office, and be rewarded by the electorate for doing so rarely occurs in practice.