From NBC:
PRESIDENT PLAYS CHESS GAME WITH SABER-RATTLING CHINESE -- The President engages both Sam and Toby in intricate chess matches that underscore the wily game of brinkmanship Bartlet is playing with the Chinese who threaten to turn their war games in the Taiwan Strait into the real thing if Taiwan begins test-firing their new U.S. Patriot defense missiles. Meanwhile, Josh is edgy about every vote out of the 42 cast in a remote New Hampshire burg that are counted immediately and always predict the winner of the day's crucial state primary. Elsewhere, a mischievous C.J. tries to upset Charlie by not accounting for her copy of the President's top-secret daily schedule -- prompting a war of mischievous games and tricks.

From TVGuide
On the day before the New Hampshire primary the President plays a game of diplomatic and military chess with the Chinese government over Taiwan while playing games of actual chess with Toby and Sam (on chessboards given him by the Prime Minister of India). Up in New Hampshire, the small town of Hartsfield's Landing will vote at midnight and Josh is determined that Bartlet not lose there. So Donna draws an assignment that gives new meaning to the phrase "retail politics."