The common perception is that most illegal aliens come across the border with Mexico, but most experts still believe that between 40% and 50% of illegals are actually people who came legally and overstayed their visas. According to a 2006 study by the Pew Research Center, “Nearly half of all the unauthorized migrants now living in the United States entered the country legally through a port of entry such as an airport or a border crossing point where they were subject to inspection by immigration officials.” In other words, these folks aren’t “undocumented” at all; they’ve just slipped through the cracks because enforcement has long been, shall we say, lacking.

If the giant bureaucracies of the Social Security Administration, Internal Revenue Service and Department of Homeland Security could work together, illegals who’ve overstayed would be easier to identify. (Maybe if the IRS wasn’t so busy targeting conservatives… Just a thought.)

Well, the Associated Press reports, there’s an effort afoot to track those who overstay visas: “U.S. Customs and Border Protection will begin capturing facial and eye scans of foreigners entering the country at San Diego’s Otay Mesa port of entry on foot. By February, foreigners going to Mexico on foot through the checkpoint will get scanned. The trial run, which lasts through the end of June, will help determine if authorities expand biometric screening to foreigners at all land crossings on the 1,954-mile border with Mexico. Authorities will look at the accuracy of the cameras.” The problem has never been the law. Congress has demanded these scans for more than 20 years. Again, it’s lack of enforcement that presents the biggest problem. And a legitimate tracking system will go a long way toward fixing it.