I vote green. Americans can't unless they're willing to throw their vote away

Not necessarily, you can vote for someone who invests in nuclear over someone who invests back into coal

Cars are a tiny fraction of a country's carbon footprint

Maybe, but there are other steps that you can take to minimize your print. Something like a solar array. Sure these are very small steps but they aren't a money sink like they used to be and if enough people adopt them, they could do something.