Carter? ... He signed it into law
Reagan? .. The standards rose every year during his 8 yrs in office
Bush I? ... Not a word against it and the standards peaked during his 4 yrs
Clinton? .. A notorious greenie-weenie
Bush II? .. He demanded that Congress jump the CAFE standards from 27 to 35 (+30%) - and he got his wish
Obama? .. 35 to 54.5 (+55%)
Look up the history of CAFE on Wiki...
This is simply false. Just because you are not personally aware of what is technically possible doesn't mean that major innovations are not already in development. Remember this wasn't done in a vacuum. Every automaker had to sign off on the agreement. In fact most were present and in full agreement that the new standards could be met in the timeframe required.The Obama Administration is mandating: technology that doesn't exist, cars we do not want to drive, electric vehicles or some combination of the 3.
Again I'll direct you to HR 1380 which is ready to be passed by Congress and signed by the President as an example of what's just over the horizon. What if your diesel pickup normally got 35 - 40 mpg every single day? That technology already exists with GM and Cummins at the forefront.