The Republican era in Congress staggered toward a close with lawmakers trying to hold together a fragile agreement on a massive tax and trade legislation considered essential before they can adjourn.

House votes on the package, which includes some $38 billion in tax breaks for businesses, higher education costs and schoolteachers, were delayed until Friday because of rebellions from both the House and Senate over its dozens of different provisions. Votes had been scheduled Thursday evening.

If the disputes are resolved, both the House and Senate would vote on the measure Friday. Another vote, on a bill to keep federal programs funded through next February, would conclude work for the year.

With that the Republican control of Congress, lasting 12 years in the House, would be over, setting the stage for the 110th Congress to convene in January with Democrats in the majority in both the House and the Senate.

As is often the case at the end of the session, congressional leaders tried to lump popular items with other more contentious measures.

The trade portion establishes permanent normal trade relations with Vietnam, which is generally supported, with the extension of trade benefits for sub-Saharan Africa, Haiti and Andean nations. The Haiti provisions in particular raised red flags with lawmakers trying to protect home state textile industries.

Attached to the tax measures are a move to block the administration from imposing a 5 percent cut in Medicare payments to doctors, at a cost estimated at $10 billion or more a year.

The search for ways to pay for this and other expensive programs raised other problems. Some lawmakers objected to a plan to ease budget shortfalls in a federal-state program providing health insurance coverage to low-income children. New Yorkers were angry when Republicans dropped tax incentives for a rail link from Manhattan to John F. Kennedy International Airport.

Under Senate rules, a single senator can force considerable delay once a bill comes over from the House.

Also included is a bill to expand federal contributions to an abandoned mine reclamation program, which could cost some $5 billion over 10 years.

The legislation also promotes energy independence by opening up some 8.3 million acres in the Gulf of Mexico to oil and gas drilling.

“This package could face obstacles to passage in the Senate, and I will be working with senators to find the smoothest path for the Senate to decide to take final action,” said Senate Majority Leader Bill Frist, R-Tenn., who will relinquish his title and retire from the Senate when Congress adjourns.

The tax breaks, several which expired on Jan. 1, include a deduction of up to $4,000 for higher education costs, a 20 percent credit for new research and development activities, and a deduction of $250 for teachers who pay for school supplies with their own money.

The bill also extends through 2008 various energy provisions now set to expire at the end of 2007, including tax credits for electricity produced from renewable resources, and for new energy-efficient homes.

As another last act, Congress will vote to continue federal spending at fiscal 2006 levels through Feb. 15, a measure necessitated because lawmakers failed to pass any of the annual spending bills for the fiscal year 2007 beginning Oct. 1 except those dealing with defense and homeland security. That will shift the burden of completing the budgetary work to the new Democratic Congress.

“They are going to leave a mess as they go out,” said Speaker-to-be Nancy Pelosi, D-Calif. “It’s been a do-nothing Congress, and as they go out the door, they are going to validate the decision of the American people that change was necessary.”

The offices of Pelosi and the next Senate Majority Leader, Harry Reid of Nevada, said they will try to attach to the funding bill a provision denying members of Congress the $3,300 pay raise they are due to get on Jan. 1, boosting the salary for a rank-and-file member to $168,500.

They said it was unconscionable that lawmakers get another raise when the federal minimum wage has been stuck at $5.15 an hour for the past 10 years.

The House and Senate on Friday also may take final action on an agreement allowing the United States to ship civilian nuclear fuel and technology to India.

On Thursday, Congress:

— Confirmed cancer surgeon Andrew von Eschenbach to head the Food and Drug Administration.

— Passed legislation codifying administration policy of denying all but humanitarian aid to the ruling Hamas government in Palestine.

— Sent to the president a pipeline safety bill motivated by the suspension of oil production in Alaska last summer due to poorly maintained pipelines.

— Agreed to spend almost $1 billion over the next five years to study the causes of autism.

On the Net:

Bill summary:

http://waysandmeans.house.gov/ResourceKits.asp?section2544