Millions of illegal migrant farmers, hotel maids and others working in the shadows of American society would be freed from the threat of deportation for at least three years and could get a chance — although probably remote for most — at permanent legal U.S. status under an election-year proposal President Bush (searchis asking Congress to approve.

Bush was to promote a major overhaul of American immigration policy — and break a virtual silence on the issue since the Sept. 11, 2001 (search), attacks — before scores of immigration-rights advocates in the East Room on Wednesday.

The president was to argue that his plan would make America safer by giving the government a better idea of who was crossing U.S. borders, bolster the economy by meeting employers' need for willing low-wage workers, and fulfill a mandate for compassion by guaranteeing the rights and legitimacy of illegal workers (search), according to senior administration officials who briefed reporters Tuesday.

Likely to be left unsaid during the president's speech were the political dividends White House advisers hoped the proposal would pay.

By dangling the prospect of legal status to some 8 million illegal immigrants now estimated to be in this country, about half of them Mexican, Bush was granting a top priority of the business community while making his most aggressive move yet to court Latino voters. He won just over one-third of that constituency in 2000 but wants to expand his support in the community to better his chances for re-election in November.

The proposal would provide a way for illegal immigrants who can show they have employment to work legally, although temporarily, in the United States. The new "temporary worker program," which also would include people still in their native countries who have a job lined up in the United States, would not, like the temporary visa programs already in existence that involve mostly technical experts, apply only to a certain sector of the economy or industry.

Much of the detail of president's proposal was to be worked out by Congress in future negotiations with the White House.

For instance, Bush wants to increase the nation's yearly allotment of green cards that allow for permanent U.S. residency, but won't say by how much, the officials said. Approximately 140,000 green cards a year are issued now.

He also wants the workers' first three-year term in the program to be renewable but won't say for how long; he won't set the amount workers should pay to apply for the program; and he won't specify how to enforce the requirement that no American worker wants the job the foreign worker is taking, according to the officials, who spoke on condition of anonymity.

Perhaps the biggest unresolved question is how the plan will allow illegal immigrants access, which they do not now have, to the process of applying for green cards, or permanent U.S. residency.

Sensitive to the opposition of many conservatives in Bush's own party to any reward for those who broke the law when they entered the United States, the administration officials said repeatedly that the president is not proposing blanket amnesty for illegals and that the program is not linked to the green card process.

But they also said that workers accepted into the temporary program could immediately, with an employer's sponsorship, begin applying for a green card. Although these workers would get no advantage over other applicants, an illegal immigrant who attempted to apply now would simply be deported.

If permanent residency were not granted before the worker's term was up — a likely outcome given the long backlog of applicants and the relatively small percentage of applicants who receive green cards each year — the person would have to return to his or her home country to apply from there.

As a result, even though program participants would be allowed to have dependents with them and be able to move freely between their country and the United States, immigrant advocacy groups say the president's proposal falls short of the comprehensive reform they say is needed.

"Extremely disappointing," said Cecilia Munoz, vice president for policy at the National Council of La Raza. "They're proposing to invite people to be guest workers without providing any meaningful opportunity to remain in the United States to become legal permanent residents."

But Mark Krikorian, executive director of the Center for Immigration Studies, which advocates strict immigration rules, was disappointed for the opposite reason.

"It's not what the folks on the left want, which is a quick green card, but it is an amnesty nonetheless," he said. "It legalizes illegal immigrants and is going to increase the number of green cards so that people will be able to move through the system faster."

In another attempt to placate conservative critics, Bush is proposing incentives to induce the workers ultimately to return to their home countries, including allowing them to collect retirement benefits in their home countries based on Social Security taxes paid here.