Repeat: Cut off their benefits! They'll go home, or somewhere else. Aliens who are working will for the most part ask for citizenship and given a visa. It has not been tried yet because too many businesses are using them for cheap labor--more working poor, and POLITICIANS like their increasing numbers for votes! (mostly Dem but 'pubs like McCain rope in quite a few).
No nation in history has survived intact the mass invasion of foreigners who want to take, not give to the country, respect its laws, learn the dominant language, and basically want to be a part of it, not to take over the host country.
And...we are bankrupt.