[Error: unknown template qotd]I'd change the U.S. electoral laws. Switch the Senate to being elected by proportional vote (dropping the two Senators to a state thing), get house races more competitive (I don't particularly care which of many good options would be used) and the Presidency to Single Transferable Vote or something like it.

I think those changes would help revitalize our Congress and that other reforms I support would be popular enough to get through the resulting more democratic system. I'm a bit too much of a good governance type to implement my other policies by fiat.