In general, political scientists fundamentally misunderstand ideology. The greatest source of confusion is the “Liberal Conservative Myth” (LCM), which is the mistaken view held by most scholars that ideological change over time can be meaningfully described as the movement of individuals and groups toward “liberalism” or “conservatism” on a static spatial spectrum. In this view, ideological dimensions running from “liberal” to “conservative,” or “left” to “right,” have fixed and unchanging meanings. Thus, if one party has always been “liberal,” and another party has always been “conservative,” then we can conclude that the two parties’ ideologies have been relatively static over long stretches of time. This is a mistaken view of political history because, over this same time period, the very meanings of “liberalism” and “conservatism” (“left” and “right”) themselves are evolving and can hide significant party reversals. The Liberal Conservative Myth is particularly problematic for political science because much of its scholarship rests on the false premise of the LCM. This has far-reaching consequences for dominant and widely used political science models like DW-NOMINATE.