Here’s the clearest glimpse yet of how the Obama campaign will use his rescue of the auto industry to go on offense against the eventual GOP candidate in swing states that were hit hard by the economy.

The Obama campaign is going up with this new ad in Michigan in advance of the GOP primary, accusing the GOP candidates of turning their backs on the auto industry and describing Obama’s auto bailout as an American manufacturing success story:

The ad’s opening line — “made in America” — displays a trace of economic nationalism, and it goes on to say: “When a million jobs were on the line, every Republican candidate turned their back, even said, `Let Detroit Go Bankrupt.’”

That’s a reference to Romney’s now-infamous 2008 Op ed. Romney didn’t argue for abandoning the industry; he called for a managed bankruptcy with some sort of financing guaranteed by the federal government. But many have concluded that approach wouldn’t have worked, and Romney did oppose the federal bailout, arguing with epic wrongness that it would ensure the industry’s “demise.”

The ad’s interesting timing suggests it’s designed to exploit the fact that the GOP primary is forcing the Republican candidates to tack ever rightward on the core ideological question of whether govenrment should play any role in intervening in the economy to save huge numbers of American jobs.

Their rightward lurch on this question is taking them far out of the mainstream. Yesterday’s NBC/WSJ poll found that 63 percent of registered Michigan voters think the auto bailout was a good idea, a position shared by 61 percent of independents and even 42 percent of likely GOP primary voters. A majority of Michigan voters say Obama deserves credit for the industry’s recovery.

Yet despite this, and despite the continuing good news about the industry, the rightward pull of the primary has forced the GOP candidates to resort to comical contortions in their quest to somehow argue that the auto bailout wasn’t a success.

The new Obama plan to cut taxes on manufactures — combined with his push for government incentives to encourage manufacturers to bring back American jobs — signal that the surprise revival of American manufacturing will be central to his reeelection message. Whether that will offset continuing high disapproval of Obama’s overall economic performance remains to be seen, but the auto-bailout will be Exhibit A in this case.