In my last column, I wrote about executive powers and the murkiness of what exactly the limits might be in modern times. Last week, the Senate Judiciary Committee, under the chairmanship of Sen. Lindsey Graham, R-S.C., held hearings on the likely next attorney general, William Barr. This column explores whom Barr is and what we learned in the hearings.William BarrBarr was born and raised in New York. His parents were both faculty members at Columbia University. Barr received both his B.A. and his M.A. in government studies …