Transportation groups of all shapes and sizes have been concerned that the Senate’s forthcoming climate bill could set back the prospects for a federal transportation measure by imposing extra carbon fees on Big Oil — which would then be passed on to customers at the pump, effectively increasing the gas tax for purposes other than funding new infrastructure projects.

Sen. Lindsey Graham (R-SC) joined the White House in denying that his forthcoming climate bill would feature a "gas tax." (Photo: MSNBC)

But it looks like there’s no need to worry. The Obama administration yesterday gave a statement to the Wall Street Journal that sought to lock down any attempt to associate the Senate climate plan with higher fuel charges: “The Senators don’t support a gas tax, and neither does the White House."

A spokesman for Sen. Lindsey Graham (R-SC), the climate proposal’s sole GOP sponsor, also denied that the bill would include a gas tax. The bulk of the back-and-forth is a semantic battle that reflects how politically poisonous a gas tax increase remains for both parties in Washington.

But it may also suggest that Graham and his co-authors are moving away from the carbon fee they had originally conceived. Graham described the idea to The Hill last month as "an assessment on what they do in the carbon world. They are creating a carbon product, they are going to pay a fee." The cost of such a fee, he added at the time, would be partially passed on to customers at the pump.

On the whole, the fact that the White House is already denying the existence of a gas tax more than a week before the climate bill is set to emerge may not bode well for its future (not to mention that of the still-stalled six-year transportation legislation).

"So Much For Kerry-Graham-Lieberman Global Warming Gas Tax?" the press office of Sen. Jim Inhofe (R-OK) tweeted.