In 1832, Williams moved to
Pittsburgh, Pennsylvania, where he continued in private practice and edited the
Advocate, a
Whig newspaper. Williams served in the
Pennsylvania State Senate from 1838 to 1841, then returned to private practice. During the
American Civil War, Williams returned to public office, this time becoming a United States representative, a position he held from March 4, 1863 to March 4, 1869. He was considered a
Radical Republican during the
Reconstruction era. During his last term as a representative, he was involved in matters of
impeaching President
Andrew Johnson. He wrote the majority report of the
House Committee on Judiciary in support of impeachment at the conclusion of the
first impeachment inquiry against Andrew Johnson in late 1867. The House ultimately voted to reject the recommendation of impeachment at that time. Months later, after
the impeachment of Johnson, Williams served as one of the
House impeachment managers (roughly equivalent to a prosecutor) in the
impeachment trial. ==Later years, death and interment==