The Democratic party wasn't always as liberal as it is now, but that doesn't mean that the GOP had to be liberal.
The Democrats were once the establishment party and the Whigs anti establishment; many Whigs became Republicans.
Being anti establishment isn't the same as being liberal.
I do think Bryan was liberal for his time although obviously very conservative religiously.
Curious what you mean about the Whigs? Most contemporary attack ads against them from Democrats seem to have painted them as a party of monied interests (in bed with Wall Street and the railroad companies), anti-immigration and morally judgmental.
I think that Whigs were formed as an opposition party to Jackson and that Jackson was seen as an establishment President.
Ah, gotcha, that makes sense. However, I would argue that it in the minds of the Whigs (and quite possibly even the Democrats, with a much more positive spin, of course!), it was
Jackson who was the anti-establishment figure, and his reign as President was effectively the "inmates running the asylum." So, "anti-establishment" sentiment among the Whigs seemed to have a flavor much more comparable to "bring back the good ole days!" than "tear down the system!"
It's important to identify what the Republican Party of the era was. It was a nationalist developmentalist coalition with an aim to unify, industrialise and purify the American nation. Its planks were patriotism, Protestant moralism and the protective tariff. One could in a way compare the 19th century GOP to the interwar KMT in China: both had progressive elements, both set themselves against pre-industrial landlordism, but the parties were not "left" as a whole.
The Democratic Party represented everyone who felt threatened and left out of this drive for national modernisation: urban ethnics, labour unions, southern sectionalists, poor farmers and so on. They saw the Republican vision for America as exclusivist and hierarchical: a corrupt nexus of big business and federal government steamrolling the common man under the presumption that everyone should be a good, obedient, industrious Yankee. In this context it's easy to understand why the Democratic Party absorbed the new left and the Republican Party did not.
Great response and a much more eloquent articulation of some of the things I was at least trying to say, haha.