Oh great, another one of these threads...the Republicans were inarguably to the left of the reactionary Democrats in the 1850s, 60s, and 70s, and arguably so until the 1930s, but we should keep that debate in the "historical continuity" thread (where I've just made a long new post!). By election, I'd say in 1904 Teddy was to the left of Parker and in 1924 both candidates were so conservative it was hard to tell, so I'd choose one of those two.
Alton Parker was to the left of Theodore Roosevelt. The Democrats' criticism of Teddy consisted of tirades about how Teddy was the "big business candidate," who was backed by the "trusts." Alton Parker was supported by left-leaning Democrats and personalities such as James B. Weaver and Carl Schurz. Even William Jennings Bryan ultimately supported Parker over Teddy in the general election (albeit only begrudgingly so), as Bryan was actually a constant critic of Teddy's administration, which he viewed as performative, pandering, and "not enough."
The Democrats have never been "reactionary" lol.
