Some conservative lawmakers are threatening to shut down the government rather than fund the president’s health care law when it comes time to pass a required spending bill this fall, but House Republican leaders are looking instead to the upcoming vote to raise the debt ceiling as their opportunity to attack Obamacare.

The federal government is expected to reach its borrowing limit in October and Congress will be asked to vote to increase the ceiling. Republican leaders see the vote as a better opportunity to squeeze concessions out of President Barack Obama than another necessary vote to set spending levels. 

But Republicans face one major problem: Obama has said unequivocally that he is not open to negotiate when it comes time to raise the debt ceiling, a position that Treasury Secretary Jack Lew echoed Tuesday.

“The president has been very clear. We are not going to be negotiating over the debt limit,” Lew said during an interview on CNBC’s "Squawk Box." Lew reiterated the statement when asked if Obama will demand a “clean” debt ceiling increase, with no strings attached. Obama first made the statement during a closed-door meeting with congressional Democrats on Capitol Hill in July, where he assured them that the issue of a debt limit hike was not open to discussion.

Congressional Republicans apparently think the president is bluffing. Despite his call for a clean increase, they are planning to present a list of demands before the vote to raise the debt limit.

During a conference call with members of the House Republican conference last Thursday, House Majority Leader Eric Cantor and Speaker John Boehner told members to prepare for a fight over the debt ceiling that includes demands to curb the health care law and budget cuts greater than or equal to the increase in the debt limit. 

On the Affordable Care Act, Republicans intend to request a one-year delay of the individual mandate to buy health insurance, a key piece of the law. They pointed to legislative victories in the past that were tied to debt limit increase votes, such as the Budget Control Act of 2011 and the Congressional Review Act of  1996, according to a House leadership aide.

This week, Boehner suggested that he sees the debt ceiling vote as a better vessel to promote the party’s agenda than a bill to keep the government running.

“What I’m trying to do here is to leverage the political process to produce more change than what it would produce if left to its own devices,” Boehner said during a Republican fundraiser in Boise, Idaho on Monday while discussing the forthcoming debt ceiling debate, according to the Idaho Statesman. “We’re going to have a whale of a fight.”

Read more from Yahoo! News