Immigration reform is like a puzzle with five extraordinarily difficult pieces to fit.

The first is the scope of the problem: What does the U.S. do with the estimated 11 million illegal immigrants already here, assuming we are not going to put them in freight trains and run them out of the country? Second is the demand by some business sectors--the agricultural industry comes to mind--for low-wage workers. Third is congressional concern with law enforcement. The presence of so many illegal immigrants demonstrates to some that laws are either unenforced or unenforceable. Fourth is fear of a terrorist attack carried out by foreigners on our soil.

The toughest one, though, is the fifth: politics. A top-to-bottom reform of immigration faces strong headwinds both in Congress, particularly in the president's own party, and among voters, who have no patience for anything that smacks of "amnesty" for illegal immigrants. ...

The bipartisan proposal getting a hearing at the White House now could break the impasse over reform. ...

It recognizes the obvious--there are millions of immigrants in the U.S. who are illegal and living beyond any scrutiny or control.

Illegal immigrants would get work visas good for six years, but would have to prove they have a work history in this country, no criminal record, and that there is nothing in their background that makes them a security risk. ...

If this all falls into place--a huge if--businesses would get their workers, undocumented workers would gain legal status, and the nation would get better border security. ...