The problem of Donald Trump and the Static Spectrum Fallacy

Donald Trump's transformation of Republican Party ideology has helped reveal major problems in the political science discipline's conceptualization and measurement of ideology. Most scholarship is dominated by the mistaken view that party ideology changes can best be described by parties moving "left" or "right" on a static, ideological, spatial spectrum. In reality, the meaning and content of "left" and "right" ("liberal" and "conservative") constantly evolve along with the issue positions of the two major parties. Thus, it makes no sense to describe parties as moving to the "left" or "right" over time when the very meanings of "liberalism" and "conservatism" change during the same time period. By understanding the dynamic character of ideology, we can reconcile the paradox of how Trump's Republican Party can change its ideology even while continuing to be identified with "conservatism" and the "Right."