You'd looove the income tax to be responsible for the Great Depression, but it isn't.
And Republicans had an opportunity to deal with the Depression, under Hoover. They didn't, and FDR got his chance.
Anyone who runs for President appreciates the power of the office. Some also appreciate the responsibility of the office, which is why Harding and Bush the Second are birds of a feather. They both understand the former but not the latter.
That's not a librarian tone. I respect my customers. That's the exasperated tone of a person who is tired of being addressed by someone who's doing his thinking in an ideological ghetto. That you think this is a librarian tone says more about your library experiences than my tone.