but the vast majority of electricity is produced from coal.
You think that 39% is a "vast majority"? The US is rapidly moving from coal to natural gas because the price of natural gas is falling as domestic production increases. All in all, an electric car creates slightly less pollution than a Prius.
Natural Gas 27%
In comparison with anything else? I do. An 11% spread would be a landslide in an election. I suppose I could have used better phrasing on that line, fine: "Coal is the biggest source of electricity in this country by a wide margin" Is that better?
But lets assume the whole country was on natural gas. That makes a difference how? It's still a fossil fuel, and after transmission and charging losses it's still probably less efficient than Gasoline. You put less CO2 into the atmosphere just burning gasoline than using an electric car. The only way electric cars make sense is if the power plant isn't producing CO2... either because it's nuclear or if they're sequestering it. You could go with hydroelectric but that has it's own environmental problems.
The entire country could switch to electric cars tomorrow and nothing would change in regards to our CO2 problem. In fact, it would likely get worse. If you want to get the newest fanciest car just because it's cool... fine... but realize what you're doing is no different then the assholes with the Hummers. Your cool is at the expense of my climate.