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 and Jack Ryan won the Republican primary. 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 for the U.S. Senate 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. The inequality in the candidates spending for the fall elections - $14,244,768 by Obama and $2,545,325 by Keyes - is also among the largest in history in both absolute and relative terms.