In case you needed another sign of how intense the battle over gas prices will get as the election heats up, the Obama-allied Priorities USA Action is going up with a new ad in seven swing states hitting back hard at a spot being run by an outside conservative group attacking the President over high gas prices.

Priorities USA sends over the new spot, and it ties the group funding the earlier ad attacking Obama directly to Mitt Romney.

The American Energy Alliance is spending $3.6 milion on an ad attacking Obama that blames him for the fact that gas prices “nearly doubled” since he took office (gas prices were low at the time because of the financial crisis), and amplifies multiple falsehoods, including the suggestions that Obama wants gas prices higher. Politico recently reported that the American Energy Alliance has deep ties to the oil billionaire Koch brothers.

In response, Priorities USA’s new ad — which will be running in Colorado, Florida, Iowa, Michigan, New Mexico, Nevada, Ohio and Virginia — blasts the AEA ad as funded by Big Oil, and points out that the oil industry has pledged $200 million to Romney’s campaign:

The ad says: “Who’s behind this ad smearing President Obama? Big Oil, that’s who. The money they make from high gas prices — is going right into Mitt Romney’s campaign. Big oil executives have pledged two hundred million to help him. And Mitt Romney’s pledged to protect their record profits — and their billions in special tax breaks too. These guys all profit. You pay the price.”

The battle highlights a larger war of messages and narratives between outide groups on both sides. Conservative groups are highlighting rising gas prices, and pushing the falsehood that Obama secretly wants them, to deprive Obama of credit from the improving economy and to advance the subtext that Obama cares more about a pointy-headed environmental agenda than he does about alleviating the difficulties of ordinary American consumers.

In response, Dem groups are highlighting the GOP’s ongoing protection of subsidies for Big Oil at a time of record profits to argue that Republicans are the ones selling outordinary Americans, in order to enrich special interests and the major corporations bankrolling their campaigns.

The fact that the Priorities ad directly pins the Big Oil spot on Romney — even before he’s won the GOP nomination — underscores how central the political battle over gas prices will be in the general election, which for all practical purposes is now underway.