Diesel cars got hit by a bad reputation in North America. And as I understand it, regulation as well has come to support it. It has become popular belief that they pollute much more than regular fuel. Probably because trucks use diesel and smell alot on top of making horrendously loud noises. You always see black smoke coming out of North American trucks exhaust, which spread the belief.
But things are different today, and diesel is getting a better reputation based on facts. And they are also now legal in California, which has one of the most restrictive emissions regulations in the U.S.A.
On another note, American car companies have never manufactured diesel engines on a wide scale for cars. Japanese cars neither, at least in North America. I've only ever seen VW come out with diesel engines over here, like the Golf and Jetta Turbo Diesel (TDI).
America mostly buys american cars, but less and less nowadays, more japanese.