A Nonsensical Tax

Who says we must have tax policy that makes any sense?  I was just talking with someone who took his car in for service at the local Ford dealership.  As he was admiring the Shelby Mustangs on the showroom floor, he was surprised to see an additional tax disclosed on the fuel economy label.  Ah, the gas guzzler tax!  Imposed on sports cars, but not on those Cadillac Escalades driving around that have thirsty V8 engines as well.  This is an archaic part of our federal tax system that predates the sport utility vehicle craze.  It was enacted in 1978 and is a graduated tax added to the cost of new cars (not trucks or SUV's) that do not meet certain fuel standards.  Does it make sense that a tricked out Chevy Trailblazer SS does not have to worry about this tax while the upcoming 2010 Chevy Camaro does (if GM lives that long)?  It doesn't have to!