Grover Cleveland, followed by Andrew Jackson.
1.) Grover Cleveland
2.) Andrew Jackson
3.) Woodrow Wilson
4.) Bill Clinton
5.) Harry S. Truman
6.) FDR, LBJ and Obama are about equal; the most liberal presidents we ever had
This, more or less.
Jackson is a complicated case. Like Lincoln, Jackson sort of defies conventional description.
Agree on Jackson.
It's also really interesting to think about today's social issues and ask how past liberal Democratic presidents would view them. For example, would FDR, Truman, JFK and LBJ approve gay marriage and campaign finance reform?