--dworkin@mtolympus.ari.net said:--
> It's not just an ethic, it's enshrined in the Constitution.  No ex post
> facto laws.  Ever.  The government cannot make a car meet standards
> enacted after it was manufactured.  You are only required to obey laws
> *after* they are passed and signed.

Oh, yeah? Then how come I have to burn unleaded gas? No, the 
gommint doesn't "force" me to, it just made it unavailable!

Seriously, I don't think ex post facto applies -- unless you're
talking about making owning an old bus a crime :-O. The States
can pass whatever registration laws they feel they can get
away with. The Federal Government can refuse to let us use
our gas and highway taxes locally unless certain air quality
standards are met. 

If and when refusing to register pre-1980 vehicles becomes
more politically acceptable than refusing "federal" money,
it will happen --See 21-year drinking age, see 55 MPH speed
limit.

-- 
Todd R. Schroeder          |    Without vision, a people perish.
todds@sungate.chotel.com   |      Proverbs xxix:18
'71 Campmobile