Leaders of the Sept. 11 commission warned lawmakers yesterday that the nation will hold them partly responsible if another terrorist attack occurs before Congress restructures the government's intelligence community. Nonetheless, House-Senate negotiators reported little progress in efforts to reconcile two massive bills on the topic, and Capitol insiders said there was little chance that Congress would approve a measure before next week's election.

"We are at a crossroads," commission Chairman Thomas H. Kean and Vice Chairman Lee H. Hamilton said in a statement to reporters in the Capitol. In July, when the commission released its book-length report, they said, "we noted that if the government does not act on our recommendations and if there were another attack, the American people would quickly fix responsibility for a failure. There is very little time left in this Congress to act."

The bipartisan commission's members have said they fear that momentum for reshaping the intelligence community will fade if a bill is not signed before the presidential election. The Family Steering Committee, representing relatives of people who died in the Sept. 11, 2001, terrorist attacks, said in a statement: "We are sounding an alarm. The opportunity to strengthen our intelligence system is vanishing. After three years of effort, we are on the brink of failure."

Leslie Phillips, a spokeswoman for Sen. Joseph I. Lieberman (D-Conn.), said there is little chance that the House-Senate conferees can resolve their differences and the House and Senate return to Washington for a final vote before Election Day. A more likely scenario, she said, would involve the conferees reaching an accord by the week's end, allowing Congress to approve the compromise in its "lame-duck" session scheduled to start Nov. 16.

Some reform advocates, however, said the bill's opponents would find it easy to kill or postpone it in a post-election atmosphere. If the negotiators "don't come to a resolution in the next 12 hours, we go into a lame-duck session with a dead-duck issue," former representative Tim Roemer (D-Ind.), one of the 10 commission members, said in a mid-afternoon interview.

Legislative matters that remain unfinished when the 108th Congress finally adjourns, presumably in late November, will die. New versions of the House and Senate intelligence bills, now more than 500 pages each, would have to be introduced and debated in the 109th Congress that convenes in January.

Disagreements between the House and Senate negotiators have remained essentially the same for three weeks. For example, the House bill would empower the defense secretary to continue overseeing the flow of federal funds to three intelligence-gathering agencies, including the National Security Agency, that are housed in his department. The Senate bill would give a newly created national intelligence director a larger role in shaping and managing the budgets of those agencies.

Kean, a former Republican governor of New Jersey, and Hamilton, a former Democratic House member from Indiana, reiterated yesterday that they prefer the Senate language on budgetary powers.

President Bush over the weekend called House Speaker J. Dennis Hastert (R-Ill.) and Senate Majority Leader Bill Frist (R-Tenn.), urging that lawmakers resolve their differences and send a bill to his desk soon. Some lawmakers questioned his enthusiasm, noting that the chairman of the Joint Chiefs of Staff recently sent the conference committee a letter endorsing the House's stand on budgetary matters, which they considered at odds with previous White House statements.

Hastert, campaigning for GOP candidates in Maine, met yesterday in Bangor with Sen. Susan Collins (R-Maine), leader of the Senate negotiators. Collins later said she appreciated the visit, adding that "many significant issues remain to be resolved."

"We are at a crossroads," Lee H. Hamilton, vice chairman of the Sept. 11 commission, said at the Capitol.