Did a Clinton-era mandate doom Columbia?

I've been reading about this during the past few days since the Discovery launched: that because of regulations that Clinton pushed when he was President that severely limited the use of freon, that the foam material on the outside of the space shuttle's external fuel tank became pretty lousy and that's why that piece of foam hit and doomed Columbia two and a half years ago. Pardon My English has a good post about it that's well worth a read. Personally, I think that since the shuttle program only has 5 years' of scheduled used anyway, to go back to the previous type of foam and for good measure do something that's not been done since the third-ever shuttle launch: cover the external tank in a lot of white paint. Paint tends to put a protective layer on top of whatever it's covering :-)