EVANSVILLE, Indiana (Reuters) - Democratic presidential candidate Hillary Clinton admitted on Monday it would be tough to lift the federal gasoline tax this summer as she has proposed because of a likely veto from President George W. Bush.

Clinton, a New York senator, and rival Barack Obama, a senator from Illinois, have sparred over the gasoline tax before primary elections on Tuesday in Indiana and North Carolina.

Obama has accused the former first lady of political pandering with a proposal that would not save consumers much money in the end.

Clinton says the legislation would save the average driver about $70 over the summer and should be advocated even if chances of passage are slim.

"Realistically, it's tough. I know that," she told reporters on her campaign plane on Monday.

"Do I think we can get it done, past a veto by President Bush as the ultimate blocker?" she said. "It's obviously a very difficult challenge. But that doesn't mean you don't try."