Looks like the issue of the federal gas tax will continue to be hotly debated this week, as the Democratic campaigns are continuing to trade attacks over proposals to suspend the tax for the peak summer driving months.

In its latest salvo, Hillary Clinton's campaign has released a new ad, called "What Happened?" that attacks Barack Obama for his opposition to the proposals. In the spot, which can be viewed below, a narrator asks, "What has happened to Barack Obama," then says, "He is attacking Hillary's plan to give you a break on gas prices because he doesn't have one ... Hillary wants the oil companies to pay for the gas tax this summer -- so you don't have to. Barack Obama wants you to keep paying; $8 billion in all. Hillary is the one who gets it."

As I said last week, this line from the Clinton campaign, that it wants the oil companies to pay the tax instead of consumers, is somewhat misleading. In 2000, the Congressional Research Service had this to say about the tax:

Economists know the gasoline excise tax as a "manufacturer's excise tax" because the government imposes it at production (i.e., the producer, refiner, or importer) for efficiency in collection. Economists think the tax is generally passed forward to the retailer translating into a higher retail gas sales price. Thus, the consumer ultimately pays the tax.

As noted previously, one of the main criticisms of the suspension proposal from experts on the issue is that there's no guarantee that the full savings producers would realize as a result of not having to pay the tax would be passed on to consumers.

Moreover, the ad's claim that Obama has no plan "to give you a break on gas prices" is misleading as well. It may be technically correct, as it seems to be worded carefully to be directed specifically toward the gas tax, but Obama has announced a plan. An ad his campaign released last week laid out his proposals: "Take on price gouging by oil companies. Tax their windfall profits. Invest in alternative energy. Give working families a permanent, thousand-dollar tax cut to help with rising costs."

Meanwhile, the Obama camp has just released a new response ad, called "Hometown." In the ad -- which can also be viewed below -- a narrator says:

A war that should never have been waged. An economy in turmoil. Record prices at the pump. America held hostage to foreign oil. And what does Hillary Clinton offer us?

More of the same old negative politics. Her hometown newspaper says she's taking the low road -- her attacks do nothing but harm. The same old Washington politics won't fix our problems. We need honest answers, and a president we can trust.

By the way, there's discussion of this issue elsewhere on Salon that's worth reading. Our very own Andrew Leonard has a post that deals with some comments Clinton made over the weekend, including her remark that she's "not going to put my lot in with economists" on the issue.

The Clinton ad:

The Obama ad: