Mitt Romney boasts that he is a job creator, and I believe him. If he winds up in the White House, there will be a bull market for fact-checkers.

Of all the falsehoods he has spun during his long presidential run, the uber-whopper is probably the one he's peddling right now, in his increasingly desperate bid to win crucial Ohio. It's unprecedented for a self-professed car guy to be rebuked for lying by two car companies, but this is what can happen when a candidate scales new lows of mendacity.

As you probably know, Romney's big hurdle in Ohio - especially among blue-collar workers - is the fact that he opposed the auto bailout, the rescue plan that was initiated by President Bush and successfully implemented by President Obama. He has tried to explain it away (by insisting that he did support a rescue plan, just a different kind of rescue plan), but that hasn't erased his persistent polling deficit in a state where one in eight jobs is tied to the auto industry. So he has moved to Plan B, blatant lying.

It all began on the stump last week: "I saw a story today that one of the great manufacturers in this state, Jeep, now owned by the Italians, is thinking of moving all production to China. I will fight for every job in America." Romney's remark caused a stir in northwestern Ohio, where the Chrysler jeeps are built. But Romney was lying. Bloomberg News reported last week that Fiat, the majority owner of Chrysler (having purchased Chrysler in a bailout deal approved by the Obama administration), was planning to build Jeeps in China for the Chinese market - "adding Jeep production sites rather than shifting output from North America to China." But after the right-wing blogs got done mangling the Bloomberg story (natch), it appeared that Chrysler was moving Ohio production sites to China. Romney duly repeated the false right-wing report, hoping to imply that Obama's bailout was sending jobs overseas.

Romney was instantaenously outed. A Chrysler executive wrote on the company website that the lie about shifting Ohio jobs to China "is a leap that would be difficult even for professional acrobatics....Jeep has no intention of shifting production of its Jeep models out of North America to China. It's simply reviewing the opportunities to return Jeep output to China for the world's largest auto market. U.S. Jeep assembly lines will continue to stay in operation. A careful and unbiased reading of the Bloomberg (story) would have saved unnecessary fantasies and extravagant comments." Moreover, Chrysler in 2013 is planning to increase its domestic Jeep workforce.

But Romney was undeterred. Remember, this is the campaign that vowed it would "not be dictated by fact-checkers." His response to Chrysler was to double down. He came up with a TV ad that is a master class in false insinuation. The key passage:

"Obama took GM and Chrysler into bankruptcy and sold Chrysler to Italians who are going to build Jeeps in China. Mitt Romney will fight for every American job."

The ad never explicitly claims that Chrysler is moving jobs from Ohio to China. It simply leaves that impression, by juxtaposing "Jeeps in China" with the line "Mitt Romney will fight for every American job" - supposedly unlike Obama, who sold off Chrysler to the "Italians."

It's amazing how much deception Romney can pack into a pair of sentences. For starters, this is the guy from Bain, which long ago pioneered the out-sourcing of American jobs. Second, criticially-ill Chrysler had been trying to sell itself to Fiat long before Obama took office. Third, Fiat's 2009 acquisition (in a deal overseen by Obama) has been a domestic boon. The Toledo plant in vote-rich northwest Ohio is back to full capacity, and Chrysler's Detroit plant is working three shifts.

But Romney's ad is still on the air, and that has prompted yet another rebuke from the car company. In a statement yesterday, Fiat CEO Sergio Marchionne said: "Jeep assembly lines will remain in operation in the United States and will constitute the backbone of the brand. It is inaccurate to suggest anything different."

Romney's response? He doubled down again yesterday, this time releasing a new radio ad that insinuates the same lie about Chrysler - and adds a new one about General Motors, the other company that has benefited from Obama's rescue plan. According to Romney's radio riff, GM is shifting 15,000 American jobs to China - thus prompting this public outburst from a GM spokesman:

"We've clearly entered some parallel universe during these last few days. No amount of campaign politics at its cynical worst will diminish our record of creating jobs in the U.S. and repatriating profits back to this country."

It's exceedingly rare for corporations to react that way in the midst of a campaign; only someone like Romney, a veritable pioneer of post-truth politics, can trigger such a reaction. After all, GM was able to recognize the lie right away. It did cut 15,000 U.S. jobs - but virtually all the cuts came in early 2009, before the Obama rescue plan, and it has added domestic jobs in the years since.

Romney's car cons have been mercilessly fact-checked in Ohio - to the point where he now risks a backlash among the clued-in workers. His last round of lying could wind up costing him votes in the state he arguably needs most. No Republican has ever won the White House without winning Ohio, and it would be rough justice if - finally - he is held accountable for his serial deceptions.

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