CAFE, and the underlying principle behind it, is a joke as meaningful legislation to reduce foreign importation of oil.
For those who look at barrels imported/day, from 1975 (when CAFE was enacted) to 1985 (when the regulations were in full force), actual imported barrels/day dropped from about 4,000 to ~3,000. However, since then, they’ve climbed to nearly 10,000 today.
(see: http://www.economagic.com/em-cgi/data.exe/doeme/coimpus )
And what’s driving this (pun intended)? Average annual miles driven. This in the US has steadily increased, resulting in overall increases in consumption - despite improving MPG averages from 14 to 27.
(See: http://www.dollarsandsense.org/archives/1998/0798breslow.html )
So unless there’s a mechanism to dis-incentivize usage of gasoline (e.g. higher prices), then any efficiency mandate will be meaningless.
Oh, and one reason why the domestics got behind this legislation is a little-publicized part - California (via CARB) won’t be able to set their own CO2 standards vs. the EPA. Therefore, designing a car for the USDM became alot easier.
Oh, and before anyone freaks, this 35 MPG limit is the one using the old EPA testing regimen, which works out closer to 27-28 real-world MPG - something relatively easily do-able in the short-term.