The upcoming fight over the nation's borrowing limit could prove to be the biggest test yet of House Speaker John Boehner's leadership, and the pressure fellow Republicans are putting on the speaker to secure billions in spending cuts as part of any deal could lead to the first government shutdown in 17 years.

Boehner, R-Ohio, has run out of wiggle room with a restive rank and file that simply won't tolerate raising the debt ceiling without spending reform, GOP operatives said.

"If Boehner were to be viewed as caving into Obama's demands and the spending cuts fell short of expectations, then his effectiveness for the remainder of his term would be limited, to say the least," one top GOP operative told The Washington Examiner.

The federal government is expected to hit its $16.4 trillion borrowing limit in a matter of weeks. If Congress doesn't allow it to borrow more, the federal government could default on its obligations for the first time and shut down for the first time since 1996.

President Obama, however, said he's not even going to debate the debt ceiling -- let alone additional spending cuts -- with Republicans. Yet Boehner, who last week allowed a tax increase through the House, not only has to negotiate but must win billions in cuts this time, GOP lawmakers said.

Boehner's new resolve comes after conservatives rallied nearly enough opposition to deny him re-election as the chamber's leader. He won by just seven votes. Conservatives are angry over the fiscal cliff deal they had to accept, which granted the tax increase Obama wanted but not the spending cuts Republicans were demanding.

The deal, Republicans said, was a "cave to the president and the [Democratic] Senate."

"If you are going to be our speaker," said Rep. Walter Jones, R-N.C., "you've got to get a lot tougher."

Boehner's allies say he capitulated on the fiscal cliff fight because he has his eye on the looming debt ceiling negotiations, where polling shows the public agrees spending cuts should be part of the deal.

"I think we are going to have to stand our ground," said Rep. Robert Aderholt, R-Ala., who joined most of the House Republicans who opposed the cliff deal. "I think the speaker is in a position now that he knows he's got to fight tough with the president, and I think he will."

Senate Republicans also say they will insist spending cuts be part of any agreement to raise the debt ceiling.

Senate Minority Leader Mitch McConnell, R-Ky., who devised the fiscal cliff deal with Vice President Biden, wrote in an op-ed on Yahoo News last week that Democrats should gird themselves for a fight.

"The conversation," he said, "turns to cutting spending on the government programs that are the real source of the nation's fiscal imbalance."