Actually, is it really possible to be a liberal on "social" issue but not on "economic" issues? Why? The social issues are very costly and affect the economy. LBJ started a $5 trillion expenditure to fight poverty. The program was expanded by Nixon, and still went on under Bill Clinton and now GWB too.
Actually when he said social issues I think he was talking about abortion, gay rights, gun rights and similar issues. Spending on programs to fight poverty would predominantly be an economic issue.