LAGUNA NIGUEL, Calif. — The delivery trucks began arriving with their precious parcels before daybreak, lining up outside a massive government edifice that rises above Orange County’s suburban sprawl.

On Monday, the starting gun went off on application season for skilled-worker visas, known as H-1B visas, which allow employers, primarily technology companies, to bring in foreign workers for three years at a time. For the last few years, the federal government has been so overwhelmed by applications that it has stopped accepting them within a week of opening day, hence the line of trucks trying to deliver applications before the doors close on the program for another year.

And this year, the rush has escalated to an all-out scramble because the future of the H-1B program is unclear.

Hailed by proponents as vital to American innovation, the program has also been criticized as a scheme to displace United States workers with cheaper foreign labor. President Trump has vowed to overhaul it, and lawmakers from both parties have drafted bills to alter it.