Complex sentence: Before being confirmed as a judge he was the Principal Deputy Solicitor General of the United States and he has argued 25 cases before the U.S. Supreme Court and was also a lecturer at Harvard Law School.
Split into simpler sentences: Before being confirmed as a judge, he was the Principal Deputy Solicitor General of the United States and has argued 25 cases before the U.S. Supreme Court. He was also a lecturer at Harvard Law School.