Abe Lincoln was a liberal and was even considered to be a radical by the conservatives of his day. He would be a Democrat today.
The former Dixiecrats, southern Democrats whose ancestors would rather have died than voted for the party of Lincoln, now vote for Republicans on the federal level.
Edit: I don't know where people get these strange ideas about John F. Kennedy. Kennedy said:
"But if by a 'Liberal' they mean someone who looks ahead and not behind, someone who welcomes new ideas without rigid reactions, someone who cares about the welfare of the people -- their health, their housing, their schools, their jobs, their civil rights, and their civil liberties -- someone who believes we can break through the stalemate and suspicions that grip us in our policies abroad, if that is what they mean by a 'Liberal,' then I'm proud to say I'm a 'Liberal.' "
JFK was a very progressive liberal.
JFK also said:
"And the only basic issue in the 1960 campaign is whether our government WILL FALL IN A CONSERVATIVE RUT AND DIE THERE [emphasis added], or whether we will move ahead in the liberal spirit of daring, of breaking new ground, of doing in our generation what Woodrow Wilson and Franklin Roosevelt and Harry Truman and Adlai Stevenson did in their time of influence and responsibility."
Those words are still true today.