The plan would create a temporary worker program to bring new arrivals to the U.S. A separate program would cover agricultural workers. New high-tech enforcement measures also would be instituted to verify that workers are here legally.

The compromise came after weeks of painstaking closed-door negotiations that brought the most liberal Democrats and the most conservative Republicans together with President Bush's Cabinet officers to produce a highly complex measure that carries heavy political consequences.

Sen. Edward M. Kennedy, D-Mass., said he expects Bush to endorse the agreement.

"Politics is the art of the possible, and the agreement we just reached is the best possible chance we will have in years to secure our borders and bring millions of people out of the shadows and into the sunshine of America," Kennedy said.

Anticipating criticism from conservatives, Sen. Arlen Specter, R-Pa., said, "It is not amnesty. This will restore the rule of law."

The accord sets the stage for what promises to be a bruising battle next week in the Senate on one of Bush's top non-war priorities. The president has said he wants to sign an immigration bill by summer's end.

The key breakthrough came when negotiators struck a bargain on a so-called "point system" that would for the first time prioritize immigrants' education and skill level over family connections in deciding how to award green cards.

The draft bill "gives a path out of the shadows and toward legal status for those who are currently here" illegally, said Sen. Dianne Feinstein, D-Calif.

The immigration issue also divides both parties in the House, which isn't expected to act unless the Senate passes a bill first.

The proposed agreement would allow illegal immigrants to come forward and obtain a "Z visa" and — after paying fees and a $5,000 fine — ultimately get on track for permanent residency, which could take between eight and 13 years. Heads of household would have to return to their home countries first.

They could come forward right away to claim a probationary card that would let them live and work legally in the U.S., but could not begin the path to permanent residency or citizenship until border security improvements and the high-tech worker identification program were completed.

A new temporary guest worker program would also have to wait until those so-called "triggers" had been activated.

Those workers would have to return home after work stints of two years, with little opportunity to gain permanent legal status or ever become U.S. citizens. They could renew their guest worker visas twice, but would be required to leave for a year in between each time.

Democrats had pressed instead for guest workers to be permitted to stay and work indefinitely in the U.S.

In perhaps the most hotly debated change, the proposed plan would shift from an immigration system primarily weighted toward family ties toward one with preferences for people with advanced degrees and sophisticated skills. Republicans have long sought such revisions, which they say are needed to end "chain migration" that harms the economy, while some Democrats and liberal groups say it's an unfair system that rips families apart.

Family connections alone would no longer be enough to qualify for a green card — except for spouses and minor children of U.S. citizens.