Lisa Sherborne was a reporter for Vanity Fair who was assigned to do a profile piece on Sam Seaborn, her former fiancé.
Lisa is shown mainly covering Sam during the State of the Union address. Sam tells her how they almost included a part about curing cancer within the speech but decided it would be best to leave it out.
Throughout the episode we see a growing tension between Sam and Lisa which most likely stems from their previous engagement that was broken by Sam so that he could join the Bartlet campaign.
Due to the obvious tension between Sam and Lisa, Lisa tells Sam that she will be passing the assignment to another reporter so that Sam can feel more comfortable with the profile.