How are legislative outcomes shaped by multidimensional negotiations? Examining the legislative politics of U.S. immigration reforms, I show how alternating coalitions in multidimensional negotiations produce centrist legislative outcomes. In doing so, this article sheds light on a puzzling aspect of immigration policy—namely, the gap that exists between public opinion and legislative outcomes. My investigation of major immigration bills in 1986, 1996, and 2006 shows that the multidimensional nature of immigration debates contributed to the lack of dramatic reforms, by allowing legislative minorities to form alternating coalitions to block any dramatic changes.