He was actually what we now refer to as a "progressive" although I don't know why we use that term because "progressives" are very retrogressive... especially since they are NAZIs when it comes to human life in the womb...
It must be remembered, that at that time, the Democrats were the "ultra-conservative party", and the Republicans were the "Liberal Party".
What we see now in both is that the Republicans now think they are "Conservatives", while at heart they are still Liberal. And the Democrats still try to believe they are "Liberals", while at heart they still tend to be "ultra-Conservatives".
Just look at the language each uses. Democrats love slamming around labels. Be is "Black Abe" or something else, or "Racist" today. I hear almost every republican labeled as "Racist" by the Democrats, and I now to be honest tune it out. Even somebody like President Trump (who got many Urban League and NAACP awards before running) is called a "Racist", even though for most of his life he was actually a Democrat. And most Republicans did not trust him, because of that.
This can be seen in the "Tea Party". A Libertarian wing of the Republicans, founded primarily by Herman Cain. Yet, some still cream they are "racist", even though one of the founders is black.
I am very much a moderate, but hearing Democrats scream that the Tea Party was "racist" even though it was led by a black man told me all I needed to know about their claims. They were no different than their screams of "****** Abe" in 1860. All garbage, slander to try and fool people who are ignorant of reality.