Gary Hart is an American politician, lawyer, author, professor and commentator. He served as a Democratic Senator representing Colorado, and ran in the U.S. presidential elections in 1984 and again in 1988, when he was considered a frontrunner for the Democratic nomination until various news organizations reported that he was having an extramarital affair. Since retiring from the Senate, he has emerged as a consultant on national security, and continues to speak on a wide range of issues, including the environment and homeland security. In 2001, he earned a doctorate in politics from Oxford. In 2006, Hart accepted an endowed professorship at the University of Colorado at Denver. He also serves as Chairman for Council for a Livable World. He has written or co-authored numerous books and articles, including four novels, two under the pen name John Blackthorn.