Today, GOP presidential contender John McCain visited the General Motors Technical Center in Warren, Mich., where GM is developing the Chevy Volt, and used the visit to talk up his plan for the automotive sector.

In the same speech, he argued that states should be able to determine their own fuel efficiency standards. California and 16 other states have been pushing for a waiver to allow them to establish their own, tougher standards for cars and trucks, which the Bush administration denied them last December.

"It's hard for me to tell states that they can't impose whatever standards they decide to impose," McCain said.

The auto industry strongly opposes state-by-state regulations, preferring instead a single, national standard.

McCain also highlighted his "Clean Car Challenge" to spur the creation of zero emission cars. He pledges to "commit a $5,000 tax credit for each and every customer who buys a zero carbon emission car." He also called for additional tax credits for other low-emissions vehicles -- the lower the emissions, the higher the tax credit.

He touted his proposal to offer a $300 million prize for the development of a better, cheaper battery for plug-in hybrids and electric cars. The battery "should deliver a power source at 30 percent of the current costs."