Updated

The Senate opened debate Tuesday on legislation creating a new Homeland Security Department as White House officials voiced confidence that they and Democrats will settle differences over the bill.

Sen.Joseph Lieberman, the chief Senate sponsor, called the measure "the single most important thing we can do now" in building better defenses against terrorism within U.S. borders.

"If we marshal these strengths of ours, we can make another Sept. 11-type attack impossible," Lieberman, D-Conn., said in opening what is likely to be a lengthy Senate debate.

Tom Ridge, the White House homeland security chief, predicted agreement would be reached but warned anew that President Bush will not accept a version of the bill pushed by Senate Democrats. Bush says that bill would deny the president the flexibility needed to manage an agency of roughly 170,000 employees.

"I think we will get it done before they recess for the November elections," Ridge said on a Sunday television program. But he said "I would have to recommend the president veto" the bill, if it were passed in its current form in the Senate, because of a lack of managerial flexibility.

Appearing on the same program, Lieberman said, "I think the White House is making up this issue."

"It is not a real issue," he said, "and certainly not reason to veto this bill and delay the security of our defenses, the raising of our guard against terrorist attack."

Ridge and Lieberman sparred on the morning television shows as members of the House and Senate were returning from their summer vacation.

On Monday, Bush jawboned lawmakers to pass the version of the bill that he wants. "Congress needs to get moving," he told a Labor Day crowd near Pittsburgh.

Bush, who returned from his ranch in Crawford, Texas, over the holiday weekend after a month of combined leisure and business travel, invited Republican senators to the White House Tuesday afternoon to discuss the measure. "The president's message is, give me a homeland security bill that allows us to do what we need to do to protect Americans from future attacks," White House spokesman Scott McClellan said.

That was to be the first of several meetings the White House planned for this week to push Bush's legislative wish-list.

But this also is a critical campaign season for midterm elections in which the balance of power in Congress is in play. So lawmakers are hoping to get out by early October, even as they face a fast-approaching deadline for finishing work on the federal budget.

Congressional leaders will be under strong pressure to recess and then return to finish their work after the Nov. 5 midterm elections. Four incumbent Senate Democrats — Tim Johnson of South Dakota, Paul Wellstone of Minnesota, Tom Harkin of Iowa and Jean Carnahan of Missouri — are in tight races that could determine whether the party holds onto its one-seat majority.

In the 435-member House, Democrats need to pick up seven seats to end the GOP's eight-year control.

Among pending issues in addition to counterterrorism legislation are bills designed to shore up the protection of people's pensions and to overhaul U.S. energy policy. And Congress has yet to give final approval to any of the 13 federal appropriations bills for 2003.

But the first order of business for the Senate is the homeland security measure. Democrats are balking at Bush's insistence on greater power to hire and fire and a provision that would bar union membership for some of the employees who would be assigned to that agency.

Bush has argued that he needs the flexibility because the agency would be designed to respond quickly to threats against domestic security.

Ridge said Tuesday "the president believes that you can't just buckle up and bolt things together" in the new department. He said the administration needs flexibility in hiring, firing and assignments.

In an appearance on CBS' The Early Show, Ridge said that "if you limit the ability of the president to move people around within this organization, you will not have done everything you can to protect this country and our way of life."

Lieberman, in the NBC interview, declared: "I'm basically trying to stick with the tried and true civil service system."