I come to it from my parents' inclinations, in the days of LBJ vs. Goldwater, and because they remembered, firsthand, how FDR kept the country from falling apart. Oh, and from scripture. More specifically,
the Beatitudes, the Golden Rule, and the passage about "What you have done to the least of these my brethren, you have done also to me."
The Air Force very nearly radicalized me as a liberal, because in the service it didn't matter what color I was or how my plumbing worked: it mattered whether I could do the job or not. To me, that's the key thing we ought to ask: can that person do that job, or not?
In Texas we had governors who could do that job, and in DC we had a President who did that job well (LBJ) I thought, without being a crook. We also had Sam Rayburn and John Connally and Barbara Jordan standing up for the Democratic side of the equation; and later we had people like Sam Nunn and Jimmy Carter and now we have people like Joe Biden and Michelle Obama and Bill Clinton and Rachel Maddow (ok, I'm speculating there; she may be an independent). We had, and have, people who walked the walk and let their deeds speak for them, rather than spending all their time preaching.
Not that we didn't have preachers too -- guys like Robertson and Falwell and that Dallas-based Tipton fraudster, the Bakkers, and on and on and on. Of course, you had to have cable TV to know about the ones outside your hometown ... but we had virulent preachers. Most of whom apparently had no other job than to preach, and no more understanding of The Beatitudes or the gospel than to preach division and fire-and-brimstone, trying to build something worthwhile on a foundation of absolute fearmongery.
I still wonder if there's not something to the notion that if you're not a preacher who can actually, you know, heal the sick and raise the dead and make food for enormous crowds appear from tiny starting points, you ought to not just be a preacher for a living. Maybe you ought to be, too, somebody who supports your family, pays your taxes, serves your country. Does your job, instead of running for it and spending other people's money so you can refuse to treat other people as well as you want them to treat you.
(Oh, I'm unexpectedly not able to tend this for a couple hours. )
I see a lot more Democrats, even today, like our President who walk that walk than I do Republicans.