Teddy
Roosevelt was in my opinion the worst President because he gave
credibility to the progressive movement, but Woodrow Wilson, who along
with TR felt the Constitution was an impediment to human progress, both
subscribing to the idea of "le estate ce moi" (I am the state) and acted
accordingly.
Wilson fleshed out that skeleton with policies
during WWI that were blatantly unconstitutional, and became known as
America's "first fascist President". Policies that were kept
in place even after the war ended, and weren't done away with until
Harding became President. All those policies were adopted and
rebranded as "The New Deal" under FDR, and many of the fascists who
worked in Wilson's government implementing his policies became leaders
of FDR's New Deal team.
But the implementation and practical application of American governmental fascism started with Wilson. Overcoming all that fascism was started by Harding, but it was Coolidge who really did what was necessary to restore constitutionality to the American government, and as I said, if he had run in 1928 Hoover wouldn't have been elected, and FDR would most likely never been President. Both of whom were disasters to the nation, and the Constitution, and the Deep State as we know it might not have come into being.
With the release of the VENONA Intercepts in 1996 we absolutely know The FDR administration was thoroughly infested with communists, Stalinist agents, socialists, and fellow travelers, and is considered the most heavily infiltrated government int history of the world, and FDR was a party to that.
We really do need a man like Calvin Coolidge again.
The problem is so little is known about what he stood for and what he accomplished, which was a great deal, and he had the same kind of petty Republican leadership to overcome Trump has had to deal with, so the Republican leadership has always had John McCain like mental issues going back over 100 years.
The worst thing that ever happened politically in the 20th century was that Coolidge, who hated being President, didn't run for his second term in 1928. That brought Hoover to the Presidency and that led to the Depression, which led to FDR being elected and he ushered in the Great Depression, and the New Deal, which wasn't new or a deal, but it was the foundation for what we're calling the Deep State.
Recommended reading Amity Schlaes book "Coolidge". If anyone refuses to buy from Amazon, there are other sources, but I highly recommend buying it, and reading it. Amity Schlaes is a great historian, but she's not a great story teller because her books are complicated, with a lot of cross referencing of characters and events, and don't lend themselves to story telling. In this book she tells good history and a good story.