The race began in November 1998 when four-term incumbent New York Senator Daniel Patrick Moynihan announced his retirement. Both the Democratic Party and Republican Party sought high-profile candidates to compete for the open seat. By early 1999 Clinton and Mayor of New York City Rudy Giuliani were the likely respective nominees. The lead in statewide polls swung from Clinton to Giuliani and back to Clinton as the campaigns featured successful strategies, mistakes, and dealing with current events. In late April and May 2000, Giuliani's medical, romantic, marital, and political lives all collided in a tumultuous four-week period, culminating in his withdrawing from the race.
The Republicans chose lesser-known Congressman Rick Lazio to replace him. The election included a record $90 million in campaign expenditures between Clinton, Lazio, and Giuliani and national visibility. Clinton showed strength in normally Republican upstate areas and a debate blunder by Lazio solidified Clinton's previously shaky support among women. Clinton won the election in November 2000 with 55 percent of the vote to Lazio's 43 percent.