The current immigration system actually goes a long way to addressing both liberal and conservative concerns.
For the liberal, thousands of people cross the southern border and gain access to decent jobs, schooling, and an economy that provides endless goods more cheaply than anywhere else in the world. They improve their lives by coming here
For the conservatives, keeping the "guise" of "illegality" in place while not really doing a lot to keep immigrants out allows for armies of hard workers to enter the country, contribute to society, pay taxes, while being reluctant to sign up for too many welfare programs. Thus, they improve America by being here.
Any solution that goes much further in letting in more migrants "legally" will upset the conservatives, and any action that is really effective at "keeping them out" will anger the liberals.
SO THE CURRENT SYSTEM - INSTEAD OF BEING "BROKEN" - MAY IN FACT BE THE BEST COMPROMISE WE CAN COME UP WITH!!