In the old (and not so old) days you had your Harry Trumans, Scoop Jacksons, Zell Millers... but no more.
They even had Big Liberals like Hubert Humphrey, who I greatly disagreed with, but also greatly admired. Humphrey was a decent, honest man of high ethics. Nothing resembling any of these folks exists now.
My father worked on the Humphrey for president campaign. He and my mother are both dems but they now admit they are lost in the wilderness. I think the parties dumping of Leiberman did it for them