Republican presidential candidate John McCain has come under fire from the United Auto Workers over his daughter’s Toyota Prius—and how exactly she paid for it. McCain originally told The New York Times that he had purchased the Prius for daughter Meghan, joking “I ought to know the name of it. I paid for it.”

But when questioned on a local Detroit television newscast, McCain backpedaled, saying that Meghan “bought it, I believe, herself.” When the reporter pressed him further on his daughter’s decision to buy an import—reminding him that several domestic companies produce competing hybrid lines—McCain went on the defensive. “I bought American literally all my life, and I’m proud. But the important thing is to make these automobiles (so that they) are competitive.”

McCain thinks that American carmakers have a ways to go before their hybrid options catch up with the Prius’s market share. That’s not earth shattering news. It’s even less surprising that the UAW—which has faced an uphill battle signing up workers at Toyota’s American plants—would seize upon the opportunity to attack McCain over the issue. The UAW has already officially endorsed McCain’s opponent, Barack Obama.

“At a time when manufacturers are struggling under the failed Bush-McCain economic policies of the last eight years, American workers and manufacturers need a president who will be straight with what he says and consistent in his support,” said the UAW in an official statement.

The McCain campaign has long trumpeted its support for hybrid and alternative fuel technologies. In June, McCain proposed a $300 million prize for any innovator who could develop “a battery package that has the size, capacity, cost and power to leapfrog the commercially available plug-in hybrids or electric cars.” Senator Obama favors a program of tax incentives and government vehicle purchases that would seek to put a million plug-in hybrid vehicles on American roads by 2015.