The ideological split should be on vivid display as early as Wednesday if House leaders follow through on their plan to have an unusual two-part vote on the credit card/gun bill.

Under the current plan, the House would vote separately on the gun provision and the credit card elements of the bill, allowing lawmakers who favor the credit card provision but not the gun measure to split their votes and allow those who want both to have it all. The two aspects of the bill would be joined again before the legislation was sent to the White House.

The Senate approved the credit card bill on Tuesday on an overwhelming vote of 90 to 5, showing that Democrats who oppose the gun provision were not going to let it interfere with their backing of the broader legislation.

Image It is a shame. But you have to come to a realization around here that at this point in time, the N.R.A. gets the votes. - Barbara Boxer, Democrat of California Credit... Rich Pedroncelli/Associated Press

Mr. Coburn and his allies in both parties say the provision is less about guns than it is states’ rights. Under the proposal, people who are otherwise authorized under state law to have firearms would be entitled to have them in national parks and wildlife refuges unless a state law prohibited it. Currently, firearms must be unloaded and secured on those national lands, creating what backers of the bill say is a situation where someone passing through a park with a firearm can be charged with a violation.

“I don’t like guns necessarily,” Mr. Coburn said. “What I want is those constitutional rights to be protected.”

Mr. Coburn has been trying for the past two years to get the measure through Congress. The Bush administration, in its final months, had pushed through a rule change that would have allowed the guns, but in March a federal judge blocked the change. The Obama administration chose not to appeal the decision while a review of potential impacts was made.