Prospects for comprehensive immigration reform are on the rise. Voters in November replaced the GOP Congress with Democratic leadership that has shown itself to be more open to expanding legal channels for immigrant workers. Nonetheless, momentum is building for major reform — and not a minute too soon. In testimony before the Senate Judiciary Committee on March 1, Commerce Secretary Carlos Gutierrez remarked that America’s dynamic economy continues to create jobs for low-skilled workers as well as higher-skilled ones, yet the number of Americans willing to fill lower-end jobs continues to shrink.

From 1996 to 2004, the number of adult Americans without a high school education — the demographic group that typically fills low-skilled jobs — fell by 4.6 million. The biggest flaw in our immigration system is its lack of a sufficient legal channel for low-skilled immigrants who are crucial to filling that gap between demand and supply on the lower rungs of the labor ladder.

In the face of those powerful economic and demographic trends, federal enforcement efforts have failed to stem the inflow of low-skilled immigrants. Homeland Security Secretary Michael Chertoff, after reporting the administration’s increased efforts at border enforcement, told the committee that a policy of enforcement-only cannot work. He called on Congress to create a temporary worker program so that foreign workers can enter legally to fill jobs that U.S. workers do not want.

“This regulated channel for temporary workers would dramatically reduce the pressure on our borders, aid our economy and ease the task of our law enforcement agents inside the country,” Chertoff told the committee. ”There is an inextricable link between the creation of a temporary worker program and better enforcement at the border.”

The last major effort to stop illegal immigration was the Immigration Reform and Control Act of 1986. It failed because it lacked any expansion of legal immigration to meet U.S. labor needs. It legalized 2.7 million immigrants and ramped up enforcement, but with no allowance for the entry of new, legal workers, the population of illegal immigrants soon began its inevitable increase to the current level of an estimated 12 million.

Immigration reform must contain a workable temporary worker program. Such a program must create a sufficient number of visas to meet the needs of the U.S. economy. A crucial flaw in the McCain-Kennedy bill passed by the Senate last May was that it capped annual visas at 200,000 — far below actual demand.

According to Labor Department projections, our economy will continue to create a net 400,000 or more low-skilled jobs annually in service sectors such as food preparation, cleaning, construction, landscaping and retail. Aa visa cap below the actual demand in our economy would only perpetuate the problem of illegal immigration.

True reforms must also avoid stifling labor regulations that discourage legal hiring. Union leaders are pressuring Democrats to require that temporary workers be paid ”prevailing wages” — that is, artificially high, union-level wages rather than market wages. This would be a recipe for failure, because many of the jobs filled by immigrant workers are low-skilled, low-wage jobs that would simply not exist in the legal economy if union-level wages were mandated.

Adding cumbersome labor rules would only perpetuate the underground labor market created by the current system.

Finally, any reform worthy of the name must offer a path to legalization for the millions of undocumented workers already here. Deporting them all would be impractical, yet continuing indefinitely with millions living in a legal twilight zone also is unacceptable.

Waiting won’t make the problem go away. If the new Congress fails to enact comprehensive immigration reform, the alternative will be two more years of widespread illegal immigration, and no one but the smugglers at the border will benefit by it.