Senator Arnold Vinick easily wins the Republican nomination on the night of the New Jersey primary, but has difficulty picking a running mate. Choosing Reverend Don Butler would virtually guarantee him the presidency, but their differing views on abortion and religion would make it a political union rather than one based on shared ideology. The Democratic nomination is a toss-up between Santos and Russell; Hoynes is running a distant third. With no clear nominee going into the convention, the Democratic party risks appearing unsure about both Santos and Russell - a position that President Bartlet does not want the Republicans to be able to exploit.

While Vinick and the Republicans deliver a flawless albeit predictable convention, the Democratic convention looks to be more like a pie fight as there is no clear favorite. Russell tries to preempt the floor vote by hinting offers of the vice presidential nomination to both Santos and Governor Baker of Pennsylvania. Charlie and Zoey's relationship is becoming more serious, resulting in different reactions from the President and the First Lady. An air leak on the International Space Station will kill all three astronauts unless a rescue mission can be launched. NASA advises that their shuttles are unfit for flight, but then hints at another solution.

With Santos gaining momentum, the Vinick campaign devises a strategy to catch them off-guard by focusing on immigration issues: by taking a pro-immigration stance, they force Santos to spend time courting the Latino vote. A powerful Christian group is nervous about supporting a Republican presidential candidate who is pro-choice, and demands a guarantee that Vinick only appoint pro-life judges. Vinick hopes that the strong religious credentials of his running mate Sullivan will be enough to satisfy the Christian base, but inevitably finds himself in a difficult situation.

Leo's preparation for the Vice Presidential debate is going badly; Santos makes his last trip home before the election; Will and Kate continue to flirt.

The Vinick campaign struggles with the impact of the nuclear accident in California; Josh and Donna have a "moment".