WASHINGTON, May 23 EThe Senate tonight passed a broad trade bill that would give President Bush the authority to reach trade agreements that are largely immune from Congressional tinkering but would greatly increase aid to workers who lose their jobs because of foreign competition.

The 66-to-30 vote brought the White House close to a top legislative priority that administration officials say will make it easier to expand trade, allowing Mr. Bush to reach trade accords that Congress could accept or reject, but not amend.

The Senate's lopsided approval followed razor-thin passage of trade authority in the House late last year, the first time in eight years that both houses of Congress have agreed to grant the White House the enhanced negotiating powers.

That handed Mr. Bush a significant victory at a time when the administration has angered major allies abroad and free-trade conservatives at home by slapping punitive duties on imported steel and supporting huge subsidies for farmers.

The 41 Republicans who voted for the bill were joined by 24 Democrats and one independent. Five Republicans and 25 Democrats opposed it.

House and Senate negotiators now must try to reconcile substantially different versions of the bill in negotiations that will pit Democratic demands for more worker protections against Republican preferences to limit costly welfare provisions.

The compromise to grant Mr. Bush so-called trade promotion authority won the support of the Senate Democratic leadership only after weeks of partisan haggling. It would triple the money spent on aid for displaced workers to $1.2 billion annually. The government would also begin paying 70 percent of the health insurance costs for people whose jobs disappear because of imports.

"Senators realize that we cannot stick our heads in the sand and that we need to deal with globalization," said Senator Max Baucus, a Montana Democrat and a main sponsor of the bill. "But we also insisted that the benefits of trade go to workers and not just to companies."

Mr. Bush agreed to support increased aid as the price of restoring trade authority. Five presidents have had the enhanced negotiating rights, but the powers expired in 1994 and Congress repeatedly denied them to President Bill Clinton.

Robert B. Zoellick, Mr. Bush's chief trade negotiator, said today that the trade authority "will provide the administration with the tools to pry open markets and negotiate the best deals for our workers, farmers, and consumers."

Mr. Bush wants to use the authority to create the world's largest free trade zone by expanding the North American Free Trade Agreement to 31 additional countries, mostly in Latin America, by the end of his first term. By that time the administration also aims to conclude a global negotiation to liberalize trade that began late last year in Doha, Qatar.

But the bill still faces obstacles. Administration officials say Mr. Bush cannot sign the measure if it includes a Senate provision that would bar changes in American antidumping laws. The restrictions are a slap at the administration after it agreed to discuss the laws, which allow countries to retaliate against low-priced imports, in Doha.

Administration officials say they will be hard pressed to reach trade accords if Congress unilaterally takes some sensitive issues off the table. Many countries have demanded that agreements address disparities in the way nations use domestic trade laws to block imports.

The trade bill passed by the Republican-led House in December did not authorize extensive new aid for workers and it did not bar Mr. Bush from negotiating antidumping rules.

Supporters say they are optimistic that the strong Senate vote paved the way to complete work on the bill.

"There is no doubt now that we're going to get this to the president," said Senator Charles E. Grassley, Republican of Iowa.

Opponents say they expect a grueling rematch in the House, where the trade measure passed by a single vote in December and where both Democrats and Republicans had hoped to avoid a second vote close to Congressional elections.

Though the margin of victory in the Senate proved heartening to the administration, the Senate has historically supported trade with far less hesitation. The prolonged wrangling over the bill indicated growing reluctance to support trade accords among Democrats and Republicans who represent districts with large numbers of blue collar workers.

Even the Bush administration, which entered office vowing to promote trade around the world, has used protectionist measures to help steel, farm, timber and textile industries more readily than the Clinton administration did. That has created a backlash among trading partners, some analysts say.

Senator Tom Daschle of South Dakota, the majority leader, demanded a high price for pushing the bill through the Senate by insisting on extensive worker unemployment and health benefits that have not often been part of trade bills.

Republicans protested what they considered a Democratic effort to turn a relatively small trade-related program that supports retraining of workers who lose jobs to foreign competitors into a vehicle for wider health care coverage and large increases in unemployment benefits.

The bill would provide benefits to many workers indirectly affected by trade, like those who supply parts to a company that closes because of foreign competition.

Welfare provisions in the Senate bill may help the Bush administration round up a few more Democrats in the House. But they could also cost votes among free trade Republicans.

In sign of the battle to come, House Democrats have begun a drive to keep the Senate bill intact and to demand more trade concessions from the administration before the measure comes before the House.

Representative Robert T. Matsui of California, a Democrat who is often considered a bellwether on trade measures, said trade accords these days were no longer just about tariffs but also about domestic policies, like antidumping and antitrust laws. He said the administration needed to give Congress a more hands-on oversight role.

"We can't agree to allow negotiations about domestic law and regulations that Congress doesn't have the power to change," Mr. Matsui said.