Who would you name as the most effective president of the last 70 years?

Who   would you name as the most effective president of the last 70 years?      Explain being sure to consider his ability to wrest power from the   Congress. Who has been the least effective? Again consider relations with  Congress. The question does not ask who you approve of the most or least.  It has to do with effectiveness.  Using constitution, declaration of independence as support to your claim and necessary debate. 2 pages cite your source