So the missus bought me a copy of F.A. Hayek’s Road to Serfdom for my birthday this year, and I was struck by something Hayek mentioned in his foreword (for the 1956 edition). Simply put, he noted that we Americans play strange games with words.
The ones I’m thinking about are conservative and liberal. Consider their root meanings: to be conservative is to defend the status quo; to be liberal is to promote the liberty of the individual.
At the birth of the United States, these two philosophies were not conflicting. Consider: our Constitution is essentially a document that enshrines liberal values. Defense of that status quo was both a conservative and liberal position — in contrast to Europe, where conservative meant royalist and generally put one in opposition to the liberals.
Consider also our extant parties. The Republican party started out as a liberal party: the party of abolition. At the time, you could easily describe the Democrats as the conservative one: defending slavery, and the Constitution of the day. After the Civil War was over, though, the Republicans had turned into the party of government, and the Democrats, the party of the opposition.
But it was not a simple division: the Republicans (not so “Grand” or “Old” yet) still included its Radical members (still liberals, but now conservative in the defense of their victory), who counterpointed the moneyed industrialists born of the War (your stereotypical business conservatives); and the Democrats were an alliance of Northeastern Labor (liberals, leaning towards socialism) and Southern Copperheads (reactionaries, who some would call conservative).
These alliances created schizophrenic parties, ones that tried to redefine words to their pleasure. It is how you get “conservatives” who are more classically liberal than the “liberals” who defend a conservative bureaucracy.
But….. “liberal” as a descriptor of the left-wing party is a relatively new invention. They were known as “progressives” prior to “liberal.” The use of the term liberal was a reaction to the negative perception of the word “progressive.” Now that the word “liberal” is bad, they are drifting back towards the term “progressive”, which is no longer so bad.
Your first statement is part of my point — though we’d probably argue about the application of “relatively new”. The adoption of liberal as a label is about a hundred years old.
As for your other statement: progressive was originally a label that could be applied to members of both parties. Teddy Roosevelt was considered one (even leading the third party that bore the title).