By Andy Sullivan
WASHINGTON (Reuters) - Republican leaders trying to wrangle deep spending cuts from President Barack Obama face an even more implacable negotiating partner: their own rank and file.
As they struggle to reach a budget deal that would allow Congress to extend the nation's borrowing authority beyond an August 2 deadline, Republican leaders in the House of Representatives must keep an eye on a back bench that has shown a marked distaste for any sort of compromise.
Republican leaders use a telling phrase when they reject Democratic proposals: any deal that includes taxes "can't pass the House." Junior lawmakers have not been afraid to let their leaders know where they stand and even undercut them at times.
At times it's not clear who's in charge.
"The internal negotiations among the Republicans themselves in Congress, whether it's just the House or between the House and the Senate, are in an abyss," said Ethan Siegal, an analyst with The Washington Exchange, which tracks Congress for investors.
Republican leaders say no plan at this point has the votes to pass the House, and an aide said they don't see how a deal can get done. One senior Republican said talks will go right up to -- and perhaps beyond -- the brink of default.
"I think we'll be here in August," said Representative Pete Sessions, the House Republicans' top campaign official, as he left a meeting with newly elected party members. "We are not going to leave town until a proper deal gets done."
House Speaker John Boehner, the top Republican in Congress, was quietly working on an ambitious "grand bargain" with President Barack Obama, until rank-and-file members objected to the $1 trillion in tax increases that would have accompanied $3 trillion in spending cuts.
Boehner's deputy, Eric Cantor, has pitched a $2.5 trillion plan as a more modest, realistic option, but members so far have not embraced it.
Dozens aren't interested in any sort of deal at all. That means Boehner will have to rely on Democratic votes to get a deal passed, which is weakening his hand at the bargaining table even as he takes an increasingly hard-line stance.
Boehner's troops are also undermining his efforts to reassure allies in the business community that Congress will avert a default that could disrupt debt service, retirement payments, military salaries and other obligations.
"The Speaker is getting bad advice," Republican Representative Louie Gohmert said at a news conference on Wednesday. "I would encourage our Speaker, quit believing the president when he uses these scare tactics."
House Republicans may present a unified bloc on taxes, but they are far from unified on tactics.
Representative Charlie Bass told Reuters Congress should pass a short-term debt ceiling increase to buy negotiators more time. But Representative Jeff Flake said he saw no need for immediate action because he thought the Treasury Department could stave off a debt default well beyond August 2.
Even a backup plan that would pin the blame for any debt-ceiling increase on Obama isn't catching on because conservatives say it would sacrifice a chance to win deep spending cuts.
That plan was proposed by Senate Republican Leader Mitch McConnell, who is known as one of Congress' foremost tacticians, but it is not expected to pass the House as lawmakers there believe it would pass up their best chance to win deep spending cuts.
Republicans in the House and Senate face diverging pressures as the 2012 election cycle gets under way.
McConnell is eager to win control of the Senate by forcing Democrats to vote on the debt limit as many times as possible, while House Republicans are eager to hold on to their majority by delivering deep spending cuts.
The election has introduced another disruptive element: presidential candidates who are more concerned with winning primary votes in Iowa and South Carolina than in getting a deal passed in Washington.
Eight candidates have signed a pledge saying they will not back a debt-limit increase unless Congress passes an amendment to the Constitution that requires a balanced budget and a supermajority for raising taxes -- an unlikely prospect.
Representative Michele Bachmann, courting Tea Party conservatives, has said she will not vote for any debt-ceiling increase.
Boehner has in recent days touted the balanced budget amendment as a possible way to resolve the debt-ceiling standoff. That could buy him some breathing room with rank-and-file conservatives, but the measure is not expected to get the two-thirds needed for passage when it comes up for a vote next week.
(Additional reporting by Thomas Ferraro; editing by Todd Eastham)