There are several options available to U.S. employers who wish to hire foreign, non-immigrant workers on a temporary but long-term basis: H-1B visas, L-1 visas, TN status and other options. These temporary options are often sufficient to meet the needs of employer and employee. When a U.S. employer wishes to hire the services of the foreign worker on a permanent basis, however, a complex sponsorship process for the green card begins, a process that can take years. Generally (although not always) the first step in that process is labor certification. Labor certification is a process of proving that there are no qualified U.S. workers for the position being offered. If there are qualified U.S. workers - in fact, even generally speaking if there are even "minimally qualified" U.S. workers - then the foreign worker cannot be offered the position on a permanent basis. This does not necessarily mean that the foreign worker will be immediately replaced by a qualified U.S. worker, though. The foreign worker can still serve out the remainder of their existing U.S. temporary visa, and may well be able to re-apply for labor certification and be approved. But it does create a substantial inconvenience for the U.S. employer who wishes to hire a foreign worker, which does provide some protection to U.S. workers, although the process is controversial.