 On September 16, Kerry defeated O'Reilly in the Democratic primary.Democrat John F. Kerry, the incumbent since 1985, was the unsuccessful Democratic candidate for President of the United States in the 2004 election.He had historically attracted strong Republican challengers, including two former Massachusetts Republican Party Chairman, Ray Shamie in 1984, Jim Rappaport in 1990, and former state Governor William Weld in 1996.