Those are good question, and why I hedged my bets between LBJ and Carter. The main point with Carter is that he was the last president under the JFK tax rates before the worst policy in our country's history, the start of the Reagan tax cuts for the rich.
I can't really think of a ton Carter did that advanced the middle class as much as continuing previous policies - but that's partly because I'm not that well informed about Carter's agenda, other than being broadly Democratic. I recall his saying he got more of his
agenda passed than any president since and plan to review more of that. He did initiate a lot of deregulation, which was mixed for the middle classes, but lowered prices on a lot. He also appointed Paul Volcker to slash inflation.
Similar with Nixon - his presidency is a bit complex in that most of his massive harm was long-term, paving the way for the right-wing shift under Reagan - while he supported the rich, his politics were much more moderate domestically much of the time.
Think about some of the names Nixon gave the country for future destruction - The Bushes, Dick Cheney, Donald Rumsfeld, Roger Ailes, the move toward a right-wing supreme court that said money is speech, Roger Stone and many more - it was under his push for corporate America to organize politically that today's corporatocracy structure was largely formed - organizations like AEI, Heritage, Cato, and others either created or rebuilt as powerful tools of the wealthy to take over government.
