In 1972, Kerry entered electoral politics as a Democratic candidate for the United States House of Representatives in Massachusetts' 5th congressional district. Kerry won the Democratic nomination but was defeated in the general election by his Republican opponent. He subsequently worked as a radio talk show host in Lowell and as the executive director of an advocacy organization while attending the Boston College School of Law. After obtaining his juris doctor in 1976, Kerry served from 1977 to 1979 as the First Assistant District Attorney of Middlesex County, where he tried criminal cases and managed the district attorney's office. After a period in private legal practice, Kerry was elected Lieutenant Governor of Massachusetts in 1982. In 1984, Kerry was elected to the United States Senate. As a member of the Senate Committee on Foreign Relations, he led a series of hearings investigating narcotics trafficking in Latin America, which exposed aspects of the Iran–Contra affair. He was reelected to additional terms in 1990, 1996, 2002 and 2008.