GOP senators say no gas tax to pay for Obama transportation budget

The letter was signed by Republican Sens. Marco Rubio (Fla.), Kelly Ayotte (N.H.), John Barrasso (Wyo.), John Boozman (Ark.), Richard Burr (N.C.), Scott Brown (Mass.), Saxby Chambliss (Ga.), Dan Coats (Ind.), Tom Coburn (Okla.), John Cornyn (Texas), John Ensign (Nev.), Chuck Grassley (Iowa), Kay Bailey Hutchison (Texas), Johnny Isakson (Ga.), Mark Kirk (Ill.), Jon Kyl (Ariz.), Mike Johanns (Neb.), Mike Lee (Utah), John McCain (Ariz.), James Risch (Idaho), Richard Shelby (Ala.), Olympia Snowe (Maine) and John Thune (S.D.).

Transportation Secretary Ray LaHood has defended Obama's budget proposal and said the president does not want to raise the gas tax at a time of high unemployment.

LaHood has not, however, said how the Obama administration would pay for the spending increase in the budget request, usually saying the administration wants to "work with Congress" on the details.