Voters on the move: The political effectiveness of migration and its effects on state partisan composition

Recent population forecasts issued by the U.S. Census Bureau suggest that by 2030 Sunbelt migration could result in two-thirds of all Americans living in the South and West. What's more, 30% of all Americans could live in California, Texas, and Florida (U.S. Census Bureau, 2005). Regardless of whether such high levels of continued Sunbelt migration occur or other patterns emerge, population movement will have electoral implications as the composition of migration streams change the balance of party identifiers at both origins and destinations. To illustrate how migration streams can exhibit very different levels of ‘political effectiveness,’ this research substantively addresses three key issues under-examined in the current literature: 1) the ability of migration to both reinforce and dilute party strength, 2) the changes in partisanship at the origin and destination of migration streams effected through processes analogous to ‘packing’ and ‘cracking’ in electoral redistricting literature, and 3) the importance of migration selectivity. This research uses an innovative, albeit far-from-precision method to suggest how recent U.S. migration trends may portend changes in Republican and Democratic partisanship. Using 2000 Presidential election exit polls by state, along with 1995–2000 PUMS migration data, individual party identification is inferred from individual migrant characteristics. This research calls attention to and argues for research to address the highly complex relationships of migration with electoral geographies.

► Compositional effects alter partisan numbers at migrant origins and destinations.
► Partisanship is derived from socioeconomic traits and merged with migration data.
► Migrant partisanship is considerably more diverse than current literature suggests.
► Migration both dilutes and reinforces party strength through packing and cracking.
► Migration is complex in creating enduring effects across political landscapes.