Well ... uncharacteristically for them ... this whole current political discussion about "immigration reform" is not just about what to do about the 10-15 million (mostly Hispanic) illegal immigrants that are currently residing in the U.S. The Congress is actually trying to come up with a comprehensive immigration policy that can be the "law of the land" when it comes to what to do and how to govern and regulate immigration.
They're supposed to be trying to cover ALL the bases ... since the current (mostly non-existent) immigration policy is probably (at least) decades old. IF they succeed ... (and although it's looking good ... with this Congress it's still a big IF!! ) .... it will probably be the only MAJOR piece of legislation that both sides will agree on in a long time.