The fate of an overhaul of U.S. intelligence agencies rests with President Bush, who must exert more pressure on holdout Republicans if he wants compromise legislation to pass this year, a lead Senate negotiator said Sunday.

"If the president of the United States wants this bill, as commander in chief in the middle of a war, I cannot believe Republicans in the House are going to stop him from getting it," said Sen. Joseph Lieberman, D-Conn., on ABC's "This Week."

But two powerful opponents of the deal, GOP Reps. Duncan Hunter of California and James Sensenbrenner of Wisconsin, are showing no signs of wavering on a measure intended to put in place recommendations from the Sept. 11 commission (search).

Hunter, chairman of the House Armed Services Committee, has expressed concerns that the intelligence realignment could interfere with the military chain of command.

Specifically, he said the link between troops and combat support agencies that run intelligence-gathering satellites of battlefield movements would be broken. That would mean "life and death to our people in the field," Hunter told "Fox News Sunday."

Sensenbrenner, head of the House Judiciary Committee, wants the bill to deal with illegal immigration (search). "We have to do something about plugging up our immigration laws," he said.

The chairman of the Sept. 11 commission said separate legislation, debated at a later time, could address those concerns.

Tom Kean, a former Republican governor from New Jersey, joined with Lieberman in urging Bush to press harder for passage.

With the overhaul stalled after lengthy negotiations, the crucial question "is whether it will pass now or after a second attack," Kean said on NBC's "Meet the Press."

While Bush and Vice President Dick Cheney have lobbied for the bill, Kean said, "The president has got to go to work."

The House and Senate each passed its own version of an intelligence reorganization in October, leading to the negotiations that produced a tentative deal last weekend. But House Speaker Dennis Hastert, heeding Hunter and Sensenbrenner, did not allow a vote before Congress left for Thanksgiving.

Sen. Susan Collins, R-Maine, the lead negotiator for Senate Republicans, said the compromise bill has wide support in both chambers. She expressed confidence it would pass if Hastert were to schedule a vote on it when lawmakers return to the Capitol on Dec. 6.

Collins, appearing on Fox with Hunter, said the bill would not endanger U.S. troops in Iraq, Afghanistan or elsewhere. "The fact is there is nothing in this bill that in any way hinders military operations or readiness," she said.

The legislation would create a national intelligence director (search) and a national counterterrorism center, as the Sept. 11 commission recommended.

If lawmakers fail to pass an overhaul this year, they will have to start from scratch next year. With a new Congress taking office in January, bills that failed to pass in the current session expire and new lawmakers and committee leaders would have to consider any new legislation.

Former Democratic Rep. Lee Hamilton of Indiana, the Sept. 11 commission's vice chairman, said the time is now to act.

If the bill does not pass this year, then "you go back to the status quo, the structure of the intelligence community unchanged since before 9/11, and it is not likely to be changed for six months or more," Hamilton said.