Though I would say that a few ( VERY FEW ) Dem presidential candidates/presidents, after 1896, weren't quite full on Socialists. Grover Cleveland was the last of the "good" Dem presidents.
Al Smith wasn't all that much of a Socialist ( just a DIRTY TAMMANY HALL one), but also never president.
I think most folks would be shocked to know what a Socialist in 1896 was vs. today. Most of the Socialist agenda was passed. Sadly, even the Republicans accepted it. Why Eisenhower never rolled back 2+ decades of a Socialist agenda by FDR/Truman. If he had followed Harding’s example, the 1950s would’ve been an unparalleled period of economic prosperity. It was really only on the surface, and the economic crash by the late ‘50s, which propelled the Demonrats to 4-decade long control of the House and 26 year control of the Senate was an example of that.
Nixon’s big flaw was that he leaned more to the failed Keynesian model on economics. Tax cuts, spending cuts and massive government rollbacks was the way to unleash prosperity. Had he championed the latter model in 1960, he’d have easily been able to overcome the JFK/LBJ Demonrat/Mafia fraud in IL, TX, and several other states.