The 2004 United States Senate election in Illinois was held on November 2, 2004. Incumbent Republican U.S. Senator Peter Fitzgerald decided to retire after one term. The Democratic and Republican primary elections were held in March, which included a total of 15 candidates who combined to spend a record total of over $60 million seeking the open seat. State Senator Barack Obama won the Democratic primary, as Jack Ryan won the Republican primary, but three months later Ryan announced his withdrawal from the race — four days after the Chicago Tribune persuaded a California court to release child custody records. Six weeks later, the Illinois Republican State Central Committee chose former Diplomat Alan Keyes to replace Ryan as the Republican candidate. The election was the first in which both major party candidates were African American. Obama's 43% margin of victory was the largest in the state history of U.S. Senate elections.