WHO WILL BE THE DEMOCRATIC PRESIDENTIAL CANDIDATE? - It's the Democratic National Convention and the race to become the Democratic Presidential candidate has narrowed to three candidates: Russell (Gary Cole), Baker (Ed O'Neill) and Santos (Jimmy Smits). Also, Bartlet (Martin Sheen) must wrestle with the decision to launch the super-secret defense shuttle to rescue the astronauts trapped at the space station and risk national security or let them die. Also starring Ed O'Neill, Allison Janney, Brad Whitford, Josh Malina, Kristin Chenoweth, Mary McCormack, Josh Malina, Richard Schiff, Stockard Channing, Teri Polo and Janel Moloney. TV-PG