Senate Environment and Public Works Chairman James M. Inhofe said Wednesday that the GOP continues to look at a gas tax increase among other alternatives to cover shortfalls in transportation spending, characterizing the mechanism as a “user fee.”

The Oklahoma Republican also said he’s confident he will succeed in negotiating a long-term transportation authorization bill with Democrats while at the same time doing everything he can to thwart the Obama administration’s environmental agenda.

Inhofe’s comments came even as lawmakers struggle to identify viable options for shoring up the Highway Trust Fund and as the administration stands firm against opposition to EPA regulations.

At a roundtable discussion with reporters, Inhofe echoed comments made in recent days by other Senate Republicans that no options for offsetting the cost of a five- or six-year highway bill should be taken off the table. That includes an increase in the 18.4-cents-per-gallon federal gasoline tax.

Inhofe prefers to call it a “user fee,” although he also called it “the most fair tax you can have” because only drivers who need gas would have to cover that cost.   

“If you had an increase of a few cents in terms of a user fee, that’s not quite like having an increase — a doubling in the cost of energy,” he said, contrasting the gas tax with a carbon tax that would affect all electricity consumers.

But Inhofe insisted that he wasn’t defending the user fee concept as the way forward on highway spending. “I’m saying we have a lot of things to look at,” he said.

He also said he didn’t think Republicans could sell a gas tax increase alone as a bill offset, signaling that members will be searching for viable alternatives.

Inhofe, who previously led the committee from 2003 to 2007, is planning rigorous oversight over EPA regulations, an area where he thinks more Democrats will change their minds about voting with President Barack Obama as his term ends and they face reelection battles at home.

Inhofe also said he expects attempts by Congress to throw out administration rules under the Congressional Review Act to have a better chance of success than when Democrats controlled the Senate. However, that would require finding Democratic votes to help overcome a filibuster against proceeding to such a measure, which could be a difficult task with less moderate Democrats in the chamber.

Inhofe predicted that Obama’s popularity will continue to decline in the waning days of his presidency — and that such an dynamic could work in Republicans’ favor when it comes to advancing their priorities on environmental policy.

“If that’s the case, there are an awful lot of Democrats who are going to be coming up for reelection — not just 2016, but 2018 — that it’s going to be to their benefit to separate them from the president,” he said.

But Inhofe acknowledged that Obama will wield his veto pen if Congress succeeds in sending to his desk bills that would turn back his regulatory initiatives — and that it won’t be easy for Republicans to find 67 votes to override him.

When asked if there were enough votes to overcome a presidential veto of an effort to nullify the EPA’s greenhouse gas rules, Inhofe chuckled.

“I don’t know,” he said. “I wouldn’t say that.”