Flip Side of the other question. This is a difficult question for me. I probably would go with LBJ out of everyone here due to the CRA/VRA/Medicare/Medicaid even though Vietnam was a disaster and I do believe that the War on Poverty failed.
When you consider these as achievements, it's actually not that surprising when Clinton doesn't count. Carter would also make sense though because of these he has the least liberal achivements.
Carter has the least liberal achievements but he was also the least competent president by far out of these four and people forget that much of what a president does isnt really just passing conservative/liberal policies and Carter was by far the worst on that regard.
I also think his foreign policy was a disaster as well so thats not much of a positive for him here over LBJ.