The sixth season of the American political drama television series The West Wing aired in the United States on NBC from October 20, 2004, to April 6, 2005, and consisted of 22 episodes. Plot The sixth season opens with the Israeli and Palestinian delegations arriving at Camp David for peace talks. Despite problems at the summit, a deal is thrashed out by President Bartlet, but not before he fires Leo as chief of staff. Leo suffers a heart attack in the aftermath, leading to a re-shuffle of the White House staff. CJ Cregg becomes chief of staff but she finds it difficult to adapt, a fact not helped by the President's worsening multiple sclerosis and consequent interference from the First Lady in an effort to conserve his energy. Away from the White House, Josh convinces Texas Congressman Matt Santos to run for president, and after a shaky start, he finds himself in a three-way race for the Democratic nomination with Vice President Russell and former Vice President Hoynes. While the Republican primaries provide a clear winner in California Senator Arnold Vinick, a moderate, the Democratic ticket is not finalized until the Democratic National Convention, at which Santos is chosen as presidential nominee, with Leo McGarry as his running mate. Meanwhile, someone at the White House has leaked national security information to reporter Greg Brock. Cast The sixth season had star billing for twelve major roles, with nine of these filled by returning main cast members from the fifth season. The main cast members are credited alphabetically except for Jimmy Smits and Martin Sheen, who receive the "with" and "and" credits, respectively. Smits, Alda and Channing are only credited for the episodes in which they appear. Main cast Alan Alda as Arnold Vinick Stockard Channing as Abbey Bartlet Dulé Hill as Charlie Young Allison Janney as C. J. Cregg Joshua Malina as Will Bailey Mary McCormack as Kate Harper Janel Moloney as Donna Moss Richard Schiff as Toby Ziegler John Spencer as Leo McGarry Bradley Whitford as Josh Lyman Jimmy Smits as Matt Santos Martin Sheen as Josiah Bartlet Recurring cast Characters that returned in recurring roles were Gary Cole as Vice President Bob Russell, Tim Matheson as former Vice President John Hoynes and Mark Feuerstein as Senate Majority Counsel Clifford Calley. Roger Rees as British ambassador Lord John Marbury also returned for one episode. Kristin Chenoweth joined the recurring cast