This is how irrational the national debate over immigration has become: Seafood processing plants in Virginia and North Carolina haven't opened or won't last the season for lack of seasonal foreign workers. Legal, seasonal foreign workers.

Congress needs to renew a key provision of a temporary-worker visa program that, in years past, has opened the door a little wider for some seasonal workers. The employers who rely on this temporary labor force are fuming because fear of the politically charged immigration debate is threatening their businesses.

How pathetic. Congress must act -- immediately on the visa program and eventually on comprehensive immigration reform that takes realistic account of the nation's labor needs.

Without that, even workers who have filled temporary jobs and then returned home year after year -- not immigrants at all, legal or otherwise -- are finding the border closed to them.

They are people who shuck oysters and pick crab meat, who do landscaping and work at hotels when the demands on these businesses surge. The workers enter the country on H-2B visas, for nonagricultural work, and their numbers are capped each year at 66,000 nationwide. This is not nearly enough.

So, in 2005, Congress set up a program that exempts returning workers who had H-2B visas within the past three years from counting against the 66,000 cap. The provision expired in September, and Congress has been loath to extend it.

So, newspapers around the state report, the Graham and Rollins seafood distributor in Hampton has 11 employees processing crabs this year instead of its usual 100 foreign workers. Its president says the fourth-generation, family-owned business might have to close. Mattamuskeet Seafood in North Carolina hasn't even opened. The 55 Mexican workers it usually hires weren't allowed to return this spring.

Some argue that Americans should be filling these jobs anyway. But employers say they have tried to hire locally and cannot. Permanent jobs, meanwhile, will be lost if year-round businesses with seasonal spikes are forced to shut down.

"They ought to make extraordinary efforts to hire a U.S. worker," Ross Eisenbrey of The Economic Policy Institute argues in The Richmond Times-Dispatch. But how is this for extraordinary: The owner of a small landscaping business in Kitty Hawk, N.C., says she sent certified letters guaranteeing jobs to local residents referred by the employment commission. She needed workers from March to May to replace the eight to 10 Mexicans she normally hires. She got no response.

Renewal of the returning-worker program for foreigners with no desire to immigrate should be a no-brainer -- and would be, if Congress would subtract political calculations from the problem.