Sen. Tom Coburn, a well-known fiscal conservative, said today that he would back an increase in the gas tax to fund the transportation bill.

“A 6-cent-per-gallon increase in the gas tax would fund a growing transportation bill for the next 10 years,” the Oklahoma Republican said.

Coburn said that the higher gas tax would be better than the offsets in the $109 billion, two-year authorization being considered on the Senate floor.

“I can’t support [the transportation bill] because it’s not paid for, and there is no assurance it will be under what we’ve done,” Coburn said.

Most of the cost of the bill would be paid for through the highway trust fund, which is currently funded by an 18.4-cent-per-gallon gas tax.

But lawmakers still have to come up with an additional $10 billion, including transferring $3 billion from the balance of the Leaking Underground Storage Tank Trust Fund, transferring the Gas Guzzler Tax, transferring certain tariffs and changing the treatment of inherited individual retirement accounts.

Some Republicans oppose the IRA proposal, and Senate Finance Chairman Max Baucus (D-Mont.) intends to find a replacement for the provision, which would raise an estimated $4.6 billion over 10 years, about half the money the committee is trying to raise.

Coburn’s comments came as Senate Majority Leader Harry Reid (D-Nev.) cut off the ability to offer amendments in an effort to get around a threat from Sen. Rand Paul to hold up the bill, Senate Democratic aides said. The Kentucky Republican wants the Senate to consider his proposal to threaten to cut off aid to Egypt until Americans being held there are released.

Reid also filed cloture on an amendment he offered that would attach the Finance, Commerce and Banking committee portions of the bill to the underlying Environment and Public Works Committee section of the measure, which is currently on the Senate floor. The vote is set for Friday.

Paul already delayed consideration of the confirmation of a judge earlier this week when he forced the Senate to wait the full 30 hours after cloture was filed on the nomination of Adalberto Jose Jordan to join the 11th U.S. Circuit Court of Appeals. The move also kept the Senate from reverting to the transportation bill it had been considering.

There are about 20 Americans among 43 individuals who are accused of illegally receiving foreign money in a case in Egypt against local and overseas-based nongovernmental organizations that have pushed for democratic reform. The case has strained relations between the two nations.

Paul wants to use the roughly $1.3 billion a year the United States provides to Egypt in aid as an incentive for the Egyptian authorities to release the Americans.

The House transportation bill faces an uncertain future as Republican leaders said they intend to move their measure after the Presidents Day recess.

“As the Speaker said at the GOP conference meeting this morning, the highway piece will likely not be completed before the Presidents Day district work period,” a spokesman for Speaker John Boehner (R-Ohio) said.

The transportation bill was also delayed because House leaders want to clear a tentative deal to extend the payroll tax cut this week. The Speaker also wants to hold an open amendment process, which will also need a larger time commitment. There have been roughly 300 amendments that Members want to add to the measure.

House Republican leaders also postponed a Rules Committee meeting in which the transportation measure was to be considered.