It's a topic often lost in the heated battle over whether to add more border patrol agents, build a bigger fence, or deploy the US military along the border with Mexico. But in the end, most analysts agree, the United States can't stem the flow of illegal immigrants until it resolves to do one thing: punish employers who hire them.
Current law provides for sanctions against such employers, and legislation now under consideration in Congress would stiffen employer penalties.
The tougher provisions are not lost on companies here in Arizona, which now has more illegal immigrants crossing its border than any other state and which owes its decades-long growth spurt in part to a huge workforce - at least 12 percent - of undocumented laborers.
But federal enforcement has long been so weak, and employer fines so few and far between, that many here still laugh off the prospect of serious sanctions - though the laughs are a little more nervous now.
"There's a pretty universal consensus that this is the single largest missing point of our enforcement regime," says Marc Rosenblum, a visiting scholar at the Migration Policy Institute, an independent think tank in Washington that tracks the worldwide movement of people. "But there's never been enough commitment or resources thrown at it. The bills being considered now would go a long way toward addressing that problem."
The Immigration Reform and Control Act (IRCA), enacted in 1986, requires employers to verify that prospective employees are either US citizens or authorized to work here. But rather than mandate a national identity card - because of privacy reasons - the legislation gives employers wide latitude in determining eligibility. Workers can offer employers at least 25 different documents to prove they are authorized to work in the US.