Scholars explain that the ideological divide among the political elites has heightened the homogeneity in voters' ideology within parties, thereby resulting in the appearance of ideological polarization in the American electorate today. This article postulates and tests four modes of party sorting in the United States based upon: (1) if partisan voters adjust their ideology to the preference of their party elites or switch to the ideologically proximate part; and (2) whether partisan voters respond to the ideological shifts of their own party or opposition party. The empirical results suggest that the conservative voters in the Democratic Party switched to the Republican Party in favorable response to the conservative shift of the Republican Party members in Congress in past decades, whereas the liberal voters in the Republican Party changed their partisanship to Democratic in negative reaction to the rightward shift of Republican elites.Related ArticlesGershtenson, Joseph, Brian W. Smith, and William R. Mangun. 2006. “Friends of the Earth? Partisanship, Party Control of Congress, and Environmental Legislation in Congress.”Politics & Policy34 (1): 66‐92.https://doi.org/10.1111/j.1747-1346.2006.00004.xGrossmann, Matt. 2014. “The Varied Effects of Policy Cues on Partisan Opinions.”Politics & Policy42 (6): 881‐904.https://doi.org/10.1111/polp.12102Knuckey, Jonathan. 2009. “Explaining Partisan Change among Northeastern Whites.”Politics & Policy37 (6): 1331‐1355.https://doi.org/10.1111/j.1747-1346.2009.00222.x