Regarding the current illegal immigration issues, part of the problem lies in the required processes to become a United States citizen. It requires too much money (especially if the person in question does not speak English). Perhaps an easier and faster process could be put in place.
I once read a quote that said something along the lines of "When we needed immigrants, we welcomed them into our country. When we didn't, we denied being a country built on immigration." (paraphrased, but you get the idea).
Think more early 20th century Ellis Island-type processes.
P.S. Sorry for any unacceptable generalities, it really is just an *idea* to get people thinking.