When Being Good Makes Someone Else Look Bad

So can someone explain to me the “real reason” why the Feds shot down California’s proposal for a waiver to implement stricter rules on carbon emission? Is this one of those “about face” rulings? Or does it have real merit in it? I mean, if the politicians are too bought off by the motor companies to get it done, why can’t individual states implement something better? And let’s not forget, it takes a while for those cars to populate the roads en mass that can even make a positive impact on the environment… hence, the sooner, the better… The Fed’s plan looks pathetic compared to rules already in place in other industrialized nations. So if the car companies can make cleaner cars for THOSE countries, I don’t understand what the big deal is to implement the same thing in the U.S.?