"And why, regarding climate change, the U.S. government, rushing to impose unilateral cap-and-trade burdens on the sagging U.S. economy, looks increasingly like someone who bought a closetful of platform shoes and bell-bottom slacks just as disco was dying."
Platform shoes and bell-bottom slacks were early '70s, disco late 70's, the difference an eternity in pop culture. Marcia Brady wore platform shoes on the Brady Bunch in 1972 when I was in 4th grade; by the time I was in high school in 1978, when disco was king, no one would be caught dead in them, especially white-suit wearing disco divas like Tony Manero (John Travolta in Saturday Night Fever). Even the nerds like me had figured it out. Will is trying to make the point that the U.S. government is catching the climate-change wave just as it is petering out, but he's really only proven that the clever pop culture references should be left to the experts.
Or in, other words, there are some times of nerd - the clever, bow-tie wearing kind - that are just embarrassing.