The drive to create a federal Department of Homeland Security, one of President Bush's top priorities since the Sept. 11, 2001, terrorist attacks, drew close to fruition yesterday as key senators agreed to a slightly revised version of the White House's proposal.

The breakthrough came when three centrist lawmakers -- Sens. John Breaux (D-La.), Ben Nelson (D-Neb.) and Lincoln D. Chafee (R-R.I.) -- agreed with some apparent reluctance to a White House plan to resolve a dispute over worker rights, which had held up the bill for two months. The developments, on the opening day of Congress's post-election session, reflected Bush's dramatically enhanced clout since Republicans expanded their House majority and won control of the Senate in last week's elections.

With GOP leaders embracing the deal and Democrats not standing in the way, the House could approve the legislation as soon as today. The Senate, under Democratic control for several more days, could grant final approval later this week or early next week.

The agreement would give Bush nearly all the flexibility he sought to bypass civil service rules in hiring, firing and promoting the 170,000 workers from 22 agencies that would be combined into the new department. The president also could waive collective bargaining rights when national security was deemed to be at stake.

The White House made modest concessions. Government unions, for example, would get a bigger role than Bush originally wanted in handling disputes over work rules and a limit on collective bargaining waivers. Unions would have 30 days to respond to proposed work rule changes. If no agreement is reached, the department would have to send a letter to Congress explaining the dispute, which would allow for congressional protests.

Another 30 days would be allowed for mediation. But in the end, the department could implement changes it saw fit. The department would have to issue findings in writing before bargaining rights could be waived, and waivers would be limited to four years, allowing for review by a new administration.

The proposal drew a sharp dissent from the American Federation of Government Employees, the large union of federal workers. "The American public needs to know that the president's so-called compromise . . . is a Trojan horse," said union President Bobby L. Harnage. "It has nothing to do with improving security. All it does is strip federal workers of the right to defend themselves in the workplace."

The three centrist senators, who earlier offered a compromise with stronger worker protections, said the new proposal recognizes political realities while improving earlier White House positions. "This was the best we could get, knowing it would pass" anyway, Breaux said.

The bill also would allow commercial airline pilots to carry firearms in their cockpits, a proposal passed earlier by the House and Senate in separate bills.

But it does not include a Senate-approved provision calling for an independent blue-ribbon commission to look into the nation's preparedness for the Sept. 11, 2001, terrorist attacks on New York and Washington. A move to include the commission in separate intelligence legislation has also stalled.

The compromise came as the 107th Congress reconvened for a lame-duck session to wrap up unfinished business. The 108th Congress will convene in January, with Republicans deposing Democrats in the Senate and expanding their majority in the House.

In yesterday's first order of business, Vice President Cheney swore in Dean Barkley as the interim senator from Minnesota. Barkley, an independent, was appointed to succeed the late Sen. Paul D. Wellstone (D-Minn.) for the rest of the current Congress after Wellstone was killed in a plane crash Oct. 25.

Barkley declined to align himself with either party, which had the effect of keeping Democrats in narrow control of the chamber for a few days at least. Republicans will take over later this month when Missouri certifies last week's results in which James M. Talent (R) ousted Sen. Jean Carnahan (D) in a special election.

Most of the Senate's day was taken up with tributes to Wellstone, whose empty desk stood covered in black and topped with a vase of white flowers. Barkley hailed Wellstone's "unrelenting energy to fight the fight" and said he planned to carry on Wellstone's effort to expand insurance coverage for mental illnesses during his few days as a senator.

Despite optimism about passing the homeland security bill, two of Bush's other priorities -- spending bills for the current fiscal year and terrorism insurance legislation -- appeared to have little chance in the lame-duck session.

After meeting with Bush at the White House, House Republican Conference Chairman J.C. Watts (Okla.) told reporters that the bill to provide federal support for buying insurance against terrorist attacks is likely to go over to the next Congress. It has been held up by a dispute over limitations on punitive damages in lawsuits.

Instead of passing appropriations bills, Watts said, Congress will probably approve temporary funding through early January, when the new Congress will convene.

But Senate Republican Conference Chairman Rick Santorum (Pa.) said he was "very hopeful" that long-delayed legislation to overhaul bankruptcy laws will be approved. He said he also sees a "melting of the iceberg" on judicial nominations in the Senate, where Republicans have objected to Democrats' blocking of some of Bush's appointees.