In the case of Immigration, that means cutting off jobs, and holding companies accountable who employee illegal workers. There is a new bill working it's way through the system that, while greatly flawed, does try to raise this bar a little. Of course business lobbyist groups, like the US Chamber of Commerce don't like this, and still want access to the cheap labor that illegal immigration provides.
The U.S. Chamber of Commerce has criticized the bill for lacking a guest worker mechanism. Republicans are split on the issue, with some pro-business lawmakers pushing for a temporary worker plan and others adamantly opposed to giving visas to people who have entered the country illegally.
Other provisions of the bill do appear costly, and will do little to address the root cause of illegal immigration, but the idea of holding companies accountable is a good one.
The most effective and inexpensive way to address illegal immigration is to end the demand for the labor. There is no reason to come to the US, if you can not make more money than you do at home. To do this, just make sure that the economic risk to any company who has illegal workers employed on their property so great, that they will actually verify employee and contractor status. With great enough penalties and enforcement, companies will no longer turn a blind eye to illegal workers, despite the economic advantage illegal labor gives.