Click here to learn more about Environmental Action’s “pledge to pay the difference” campaign. Upon collecting 3,600 pledges, the group is hoping to tell U.S. auto makers that E.A. members will pay more for environmentally friendly vehicles–if U.S. makers create them. My bet is that the E.A. will get more that number of digital signatures.

The catch: You have to pledge to buy an American-made car if auto makers double the mileage-per-gallon of domestically manufactured models. The pledge goes like this:

“I pledge to you that if you double the mileage standard of your vehicle fleet from 27.5 mpg to 55 mpg, and your light truck/SUV fleet from 20.7 to 41.4 mpg, I will not only purchase one of them the next time I buy a new car, but I will also pay the difference of cost to increase the standard.”