re: #87 BeachDem
Was watching one of Ken Burns’s “The Roosevelts” last night and noticed that there did not seem to be pledged delegates at the Democratic convention in, i think, 1940.

Hmm. I did not know that: My interpretation from the article:

Party conventions to select nominees did not occur until 1831.
Delegates to the national convention were usually selected at state conventions whose own delegates were chosen by district conventions. Sometimes they were dominated by intrigue between political bosses who controlled delegates; the national convention was far from democratic or transparent.
In 1910, Oregon became the first state to establish a presidential preference primary, which requires delegates to the National Convention to support the winner of the primary at the convention.
By 1912, twelve states either selected delegates in primaries, used a preferential primary, or both.
By 1920 there were 20 states with primaries, but some went back, and from 1936 to 1968, 12 states used them.
The impetus for national adoption of the binding primary election was the chaotic 1968 Democratic National Convention.

Prior to 1968 most delegates were essentially Superdelegates.