INDIANAPOLIS -- The Democratic presidential candidates engaged in long-distance sparring on fuel taxes yesterday, spotlighting one of the relatively few policy differences in their increasingly heated nomination battle.

A week before this state's closely watched primary, Sen. Hillary Rodham Clinton focused on a proposal for a summer fuel tax holiday that she would pay for with a windfall profits tax on the soaring earnings of international oil companies.

"The oil companies keep making out like bandits," she said during a stop at a plant that makes wood veneers,. "There are a lot of people in Indiana who would benefit from a gas tax holiday."

Campaigning in North Carolina, the other state voting next Tuesday, Sen. Barack Obama dismissed Mrs. Clinton's plan, and a similar one from Sen. John McCain, the presumptive Republican nominee, as primary season year pandering.

"This isn't an idea designed to get you through the summer, it's designed to get them through an election," Mr. Obama said in a statement issued by his campaign.

Mrs. Clinton distinguished her plan from the a tax holiday proposal that Mr. McCain unveiled in a speech at Carnegie-Mellon University earlier this month by noting that she would pay for it -- rather than just forgoing the revenue -- by depositing the proceeds of a new windfall profits tax into the federal Highway Trust Fund, which is the beneficiary of the levies on gas and diesel fuel that she would suspend.

Critics of the tax holiday had pointed out that the lost revenue would likely cost thousands of highway construction jobs supported by the trust fund. Suspending the 18.4-cent-a-gallon federal tax and 24.4-cent diesel tax between Memorial Day and Labor Day could cost the government about $10 billion.

"Sen. Obama won't provide relief, while Sen. McCain won't pay for it," Mrs. Clinton maintained after a tour of the wood-working facility in the East Side neighborhood of the state's capital city.

In their rebuttal, however, the Obama campaign argued that Mrs. Clinton was trying to count her windfall profits tax twice as she had already suggested that such a levy be used to support research and development of alternative forms of energy.

Mr. Obama said that the only real relief from higher fuel costs would come through longer term steps toward energy independence, which he and Mrs. Clinton have offered in broadly similar terms.

"What we're talking about now is a Washington con game, and I think the American people are smarter than Washington and will see right through it," Mr. Obama said in his North Carolina remarks.

The Obama camp argues that the gas tax suspension would have only a modest benefit to the average motorist, but after her tour here, Mrs. Clinton maintained that its impact would be felt more widely throughout the economy, pointing to the plant she had just visited as an example.

"You've gotta bring those logs in; you've gotta send the finished products out, and the costs are sent down the supply chain, from the factory floor to the corner store," she said. "My gas prices agenda is a jobs agenda."

With the election looming, the Clinton campaign planned to underscore her criticism of Mr. Obama on the fuel issue in a new televisions commercial.

The McCain campaign derided Mr. Obama's criticisms noting that he had voted for a similar concept for relief from state fuel taxes while he was a member of the Illinois state senate. Mr. Obama did vote for such a holiday but later opposed a measure that would have permanently suspended the state tax.

"Sen. Obama voted for a gas tax reduction before he opposed it," McCain spokesman Tucker Bounds told the Associated Press.

After his North Carolina swing, Mr. Obama will return to campaign here today in a state where several polls have depicted the race as too close to call. A survey released by the Howey Political Report yesterday showed Mr. Obama leading Mrs. Clinton, 47 percent to 45 percent, a difference within the poll's margin of error. Mr. Obama had a double-digit lead in the same poll a month ago.

In the parallel competition for the support of the party's superdelegates, both Democrats claimed two more yesterday, but one of Mrs. Clinton's new supporters was particularly crucial for next Tuesday's contests. She came away with the big "get" of the day in North Carolina Gov. Mike Easley, who delicately observed that the New York senator makes "Rocky Balboa look like a pansy."

Mrs. Clinton also announced the support of Rep. Ike Shelton, D-Mo., the chairman of the House Armed Services Committee. Mr. Obama picked up the support of an Iowa member of the Democratic National Committee as well as that of Rep. Ben Chandler, of Kentucky, a state that hosts a primary later in May.