When I first learned about Huey Long , my mother (b.1921, grew up in Louisiana, among other places) said he was a demagogue. But I thought he sounded like a pretty good guy. He believed in Sharing the Wealth, provided free textbooks, built roads, wanted to provide minimum and maximum income levels. Stuff like that. He wasn't so great on free speech issues. But there's still good to be said of him.
He comes off pretty badly in All the King's Men, at least in the 1949 movie version. (Who knows what the 2006 version will be like.) But it still doesn't seem quite right to have named All the President's Men after the earlier work. Nixon was no populist.