114949882.0President Obama is expected to announce major changes to immigration policy before the end of 2014 — and possibly as soon as this week. On one level, this is the end of a process that started in March, when the administration first announced it was reviewing deportation policy to see how it could be made more humane. On another level, though, this is another phase in the development of an immigration system that’s been transformed over the last 20 years. To understand how we got to this point, it’s necessary to understand why immigration policy looks so different now than it did back then. Massive relief to millions of unauthorized immigrants would be an unprecedented move on Obama’s part — but it is also a reaction against trends in immigration enforcement that are themselves unprecedented. More