21. Things Fall Apart

Faced with a Democratic party in disarray in the face of the strongest Republican challenger they have ever had, Bartlet asks Leo to take charge of the potentially chaotic Democratic National Convention, while Santos considers a party-unifying vice-presidential offer from front-runner Russell. Meanwhile, the International Space Station is leaking oxygen and a rescue of the three astronauts will be difficult, and Bartlet catches Charlie leaving Zoey's bedroom after a nighttime visit.