Complex sentence: Senator Patrick Leahy, the Democratic Chairman of the Senate Judiciary Committee, questioned Mukasey and was pleased that Mukasey was committed to a new administrative rule to reduce the influence of the White House and other politicians on the staff and investigations of the Justice Department.
Split into simpler sentences: Senator Patrick Leahy, the Democratic Chairman of the Senate Judiciary Committee, submitted questions to Mukasey. He was pleased that Mukasey had agreed to commit to an administrative rule to reduce the influence of the White House and other politicians on the staff and investigations of the Justice Department.