Edwards. His voting record may represent a social liberal, but he speaks in a very populist way. Example, poverty as a moral issue.
I agree to a point, that Edwards comes across as very populist, but I think the original post was referring to their overall economic & social views being populist (Liberal economically, moderate to conservative socially)
Sure but how a candidate sells himself, and what his background is, plays a big role in how voters see them, more than any one issue would. When talking about populism, you really cannot ignore style.