South Carolina House members fired a shot across the bow of many state businesses on May 5 when they passed a bill aimed at reducing the number of illegal immigrants working in the state.

The bill requires public employers in the state, including all state agencies and political subdivisions, and any company that does business with the state to check the legal status of new employees through a U.S. Department of Homeland Security electronic verification system. The bill has been sent to the Senate, where it must get two-thirds approval to be taken up.

The vote came in a week that brought relatively empty roads and many empty classroom seats as immigrants, legal and illegal, and their supporters stayed home for a "Day Without Immigrants."

What, if anything, did we learn from the walkout? It gave us some sense of the number of people potentially affected by immigration legislation. And it signaled that any action by Congress will mean that many local business owners face a big change in the way they do business, especially in terms of harsher penalties for hiring illegal immigrants.

Gov. Mark Sanford was quick to urge the state Senate to take up the House bill before the session ends in June. In a prepared statement, the governor said he was open to a bill that would go even further, such as one proposed last year by state Sen. Scott Richardson, R-Hilton Head Island. Under Richardson's bill, any employer -- public or private -- could be fined up to $5,000 for each incident and have any licenses revoked for knowingly hiring, recruiting or referring an illegal immigrant. No action has been taken on the bill this legislative session.

"I'd give real credit to the House for passing a bill that takes a step toward sending a message that our state won't create an incentive for illegal behavior," Gov. Sanford said in his statement. "We're a nation of immigrants, but we're also a nation of laws. Legal immigration is part of what makes this country great, but we should never be in the position of sanctioning illegal behavior with a wink and a nod."

Sanford is right that there is a fundamental issue of right and wrong when it comes to illegal immigrants. We should not turn our heads to the problem of people entering this country illegally or the problem of businesses hiring illegal immigrants -- knowingly or unknowingly.

For the sake of fair wages, job protection and workplace safety, all workers should be fully documented. For the sake of publicly supported schools and other social services, they should be paying their fair share of taxes.

And for the sake of an economy that relies heavily on immigrants -- legal and illegal -- to keep up our breakneck pace, we need to prepare now for laws at the state and national levels that could greatly increase the cost of doing business here and greatly increase the difficulty in finding people to work.