The Obama campaign quickly worked itself into a froth of outrage over the ad. "Flat. Out. False," campaign manager Jim Messina said Monday. "It reeks of desperation because that's what it is." By Monday afternoon, the Obama campaign was out with its own ad responding to Romney's.

The back-and-forth over the ad wasn't just the petty fracas of a late-stage campaign. It illustrated a deeper truth: The auto bailout is helping Obama in Ohio, and Romney has never managed to blunt the president's edge on the issue.

The bailout -- accomplished via executive action in 2009 using funds from the Troubled Asset Relief Program -- was unpopular at the time. But now that the auto companies are thriving, the president often touts it as an example not just of a resurgent economy but of tough decision-making. One poll earlier this month found that 54 percent of Ohioans approved of the auto rescue, while just 37 percent did not -- and 79 percent thought the auto industry was an important issue.

The most obvious evidence that Obama is winning on the auto bailout comes in the way Republicans have fumbled around for a response. As they campaign in Ohio, Romney and his allies have trotted out a variety of counter-arguments, but none has stuck. The result is a hash of convoluted explanations and excuses:

* The bailout wasn't necessary. This is basically Romney's line. Though he famously wrote an op-ed headlined "Let Detroit Go Bankrupt," he was not, as Obama claims, advocating letting the industry fail; he called for the auto companies to be taken through a managed bankruptcy with the aid of private capital. (Even the most dedicated free-marketeers don't generally dare to argue that the auto companies were failing because they couldn't compete and deserved to die.) The major problem with this argument is that there was no such private capital to be had at the time; that's why the companies were begging for federal help.

* The bailout wasn't a big deal. That's the claim made by Ohio's Republican governor, John Kasich, who says it only created 400 new jobs. Kasich gives his own efforts to recruit business to the state more credit for the improving economy in Ohio, whose unemployment rate of 7 percent is below the national average. Democrats put the number of bailout-linked jobs as high as 850,000. The discrepancy comes from the fact that Kasich is using the narrowest possible definition -- jobs on the manufacturing line in auto plants -- whereas Democrats are using a more expansive metric, including jobs at industry suppliers and related businesses supported by the industry, such as stores where auto workers shop. Romney's campaign has also argued that Ohio voters are getting tired of Obama's pounding away at the bailout issue.

* The bailout was a good idea. Some Republicans' attempt to argue against the bailout is muddled by the fact that other Republicans supported it. A December 2008 precursor bill that died in the Senate was supported by 32 Republican House members, including eight Michigan Republicans, two Ohio Republicans, and Wisconsin Rep. Paul Ryan -- now Romney's running mate. Nine Republican senators also supported the measure, including then-Ohio Sen. George Voinovich.