* Republicans rejecting Sen. Cruz gambit on Obamacare
* House Republicans' final move on spending unclear
U.S. Senate Republicans on Tuesday appeared to fall in line with their leaders who want to pass an emergency spending bill by Sept. 30 and avoid government shutdowns, even if it means failing in a drive to destroy "Obamacare."
Republican Senator Ted Cruz, the Tea Party-backed conservative who has been pushing for gutting President Barack Obama's signature healthcare law by linking it to government funding in the new fiscal year, sought to rally support.
But his fellow Republicans were moving in the other direction one day after the party's top two leaders, Mitch McConnell and John Cornyn, refused to lend their support.
Republican Senator Lindsey Graham said he expects a majority of the Senate's 46 Republicans will reject Cruz's high-stakes maneuver that has been embraced by the Republican-led House of Representatives.
"I think most Republicans believe, no matter how sincere you are about defunding Obamacare, that this approach would blow up in our face," Graham told Reuters in a brief hallway interview on Capitol Hill.
Another senior Republican, who asked not to be identified, said a government shutdown could ruin the party's chances of winning back control of the Senate in the 2014 elections.
At the urging of Cruz and other Tea Party members, the Republican-led House of Representatives narrowly passed the bill providing government funding but without money for Obamacare. Passage came on a party-line vote on Friday.
Since Cruz launched his bid, Republican senators and their aides have been unusually candid in their impatience with the freshman senator from Texas who has his eye on a 2016 run for president.
"We will end up not shutting the government down and we will not defund Obamacare. That's how the movie ends," Republican Senator John McCain, a former presidential candidate himself, told reporters. Only when Republicans control 67 votes in the Senate - enough to override any presidential vetoes - will the party dismantle the healthcare law, McCain added.
As the Senate slowly moved through a debate that likely will lead to passing a government funding bill by Sunday, House Republicans continued to weigh their options once they receive the Senate's work.
Some congressional aides have said that a new round of House amendments were being weighed, possibly including one to repeal an unpopular medical device tax aimed at generating $30 billion in revenues over a decade to help pay for Obamacare subsidies.
SENATE PASSAGE POSSIBLE SUNDAY
Obama's Democrats, who control the Senate, 54-46, vow to remove the Obamacare defunding provision, but will first need 60 votes to clear procedural roadblocks.
If they succeed, the Senate is expected to pass a new bill by Sunday. The measure would then be returned to the House for concurrence.
The House could then approve the Senate version or try to amend it. But they would only have a day or so before current government funding expires.
At this point, it is unclear what House Republican leadership would decide to do, generating plenty of questions and anxiety.
House Republican leaders have not informed rank-and-file members what the final stage of the fight over the spending bill will look like, according to an aide to one junior Republican.
"First and foremost, he doesn't want the government to shut down," the aide said, though adding that the lawmaker was under intense pressure from conservatives back home to stop Obamacare.
"He is definitely stressed," the aide said.
Senate Majority Leader Harry Reid, a Nevada Democrat, has repeatedly declared the House-passed bill dead as long as it contains the defunding provision.
But Reid may also seek some other changes to it, said Democratic Senator Tim Kaine of Virginia.
Kaine said Reid is considering offering an amendment that would provide only enough funding to keep the government operating through Nov. 15, instead of the Dec. 15 date contained in the House-passed bill.
Kaine said Democrats hope that a shorter time-frame for temporary spending might better foster negotiations on finding a substitute to the across-the-board spending cuts that began in March.
Those indiscriminate spending cuts, which hit defense and domestic programs alike, are deeply opposed by Democrats in the Senate and House.
Once the battle over government funding bill is resolved, Congress will quickly focus on another potential fiscal crisis - a possible and unprecedented U.S. government default unless it agrees to raise the $16.7 trillion U.S. debt limit by sometime next month or early November.
Republicans are expected to place a number of demands on any bill to increase the debt limit, including one to delay for a year implementation of Obamacare, which is now set to begin to fully kick in next month.