Alex Engler’s analysis from February looks at how immigration reform could affect the House. He finds that, “while the Republican Party has a great deal to gain from successful bipartisan immigration reform, House Democrats face little benefit and even, paradoxically, the possibility of significant losses.” The main reason why:
Democrats currently control the majority of districts with large Hispanic populations. There are 39 Republican districts that are more than 20 percent Hispanic, and only five that are more than 50 percent Hispanic (compared to Democrats’ 76 and 28 districts, respectively).
This concentration of the Hispanic vote means that “a dramatic shift in Hispanic support toward Democrats would have yielded startlingly small gains in the House”:
Under the 42 percent Hispanic voting scenario, a 10 percentage point shift toward Democrats would net only one additional seat, and a 20 percentage point shift would turn only six seats. Conversely, shifts away from Democrats by Hispanics could be devastating. Under the 42 percent scenario, a 5 percentage point shift toward the GOP would have turned five races into Republican victories. A 10 percentage point shift to the right would have handed Republicans 12 seats, and a 16 percentage point shift would have flipped 21 districts. Using the lower turnout models reduces the number of seats changing hands, but the narrative remains the same.
Drum adds his two cents:
This doesn’t answer the question of which party immigration reform is likely to help. What it does say is that it’s a no-lose proposition for Republicans. Even if it turns out to help Democrats more, Republicans aren’t likely to suffer much because of it.
The Dish 