Denis E. Dillon (December 21, 1933 – August 15, 2010), was an American prosecutor and politician who served as District Attorney of Nassau County, New York, from 1975 to 2005. Dillon was well known for his opposition to abortion rights, and the issue prompted his defection to the Republican Party in 1989, having previously been one of the very few Democratic politicians to have success in Nassau County. Prior to his defection, Dillon challenged incumbent Democrat Mario Cuomo from the right in the 1986 New York gubernatorial election, finishing in third place with 3% of the vote as the nominee of the New York State Right to Life Party. First elected to a three-year term as District Attorney in 1974, Dillon was re-elected to 7 four-year terms, losing in his attempt to win a ninth term in 2005 to Democratic nominee Kathleen Rice. In the history of New York, only Robert Morgenthau of New York County (Manhattan) and William V. Grady of Dutchess County have served longer as a District Attorneys, although Robert M. Carney of Schenectady County will also surpass Dillon's mark prior to the expiration of his current term. Early life, education and career Dillon was born in 1933 into a devout Roman Catholic family in the Bronx, and spent parts of his childhood living in the borough's Woodlawn Heights neighborhood, where his father owned a bar, as well as the Rockaway Beach section of Queens and in Arlington, Virginia, an immediate suburb of the District of Columbia. Dillon graduated from Fordham University with a Bachelor's degree in 1955. Dillon graduated from Fordham University School of Law in 1962, having attended at night while working as an officer in the New York Police Department. Upon graduation, Dillon was hired by the United States Department of Justice Civil Rights Division, where he served until appointed an Assistant United States Attorney for the Eastern District of New York in 1966. In 1968, Dillon joined the Eastern District's Organized Crime Task Force, becoming its director in April 1970 and serving until he resigned to run for District Attorney on May 16, 1974. District Attorney 1974 election Dillon was originally elected in 1974 as a Democrat, defeating 12-year incumbent Republican William Cahn and Conservative Party nominee Francis B. Hearn with 52% of the vote in what The New York Times called a "major upset". The campaign between Dillon and Cahn was brutal