Check his bio
available here:
Matthews spent 15 years in politics and government, working in the White House for four years under President Jimmy Carter as a Presidential speechwriter and on the Government Reorganization Project, in the U.S. Senate for five years on the staffs of Senator Frank Moss (Utah) and Senator Edmund Muskie (Maine), and as the top aide for Speaker of the House Thomas P. “Tip†O’Neill, Jr. for six years.
Needless to say, Carter was a Democrat. So was Frank Moss, Edmund Muskie, and Tip O'Neill. Hardly the bio of a conservative.