Continuity mistake: When Bruno and Bob are poring over exit polls, they mention that Santos seems to be leading in North Dakota, and comment that it is a state that hasn't gone Democratic in forty years. While that is true in the real world, in the fictional West Wing world, it is stated in Season 4 that Bartlet won the Dakotas in his landslide reelection.
Continuity mistake: When Toby is walking back to his office from the press room with his ex-wife, the ex-wife's tag and chain keeps changing through the entire sequence. Sometimes it's over her jacket and the tag's just hanging or it's under the jacket and the tag is sitting just inside her jacket.
Continuity mistake: Bartlett is in the executive office in the residence watching four TVs at once. He hears a line in the black and white movie, a second later he rewinds it to hear the line again - he rewinds way too much and for too long, but once he stops the tape, it plays the line he wanted to hear again right away. He went too far back (for visual effect) than what in reality it would have taken.
Continuity mistake: As Margaret enters Leo's office, the bottom corner of her ID tag is tucked into the sweater's button area. It remains this way when she stops walking. The camera reverses angle for a moment, yet we can still see she isn't moving. But the angle changes back and suddenly the ID hangs freely, dead center, over the buttons. Moments later, as she turns to leave, it's again tucked in. (00:12:10)
Continuity mistake: When Ainsley Hayes and Lionel Tribbey are talking in her office, the bottled water moves from being to the right of the framed picture on her desk in the shots over her shoulder to being behind the picture in the shots of her desk from the front. (00:21:40 - 00:22:30)
Continuity mistake: When Doug, Toby, and Sam are talking to the President about how to handle the attempted repeal of the estate tax, they mention several times that it will be the President's first veto, and that it is something that he has never done before. However, in episode four of season two, "In This White House", in the scene where Sam is debating Ainsley Hayes on Capital Beat, the moderator asks why the President's education bill is different from the Republican proposed bill "which the President vetoed." So, the veto of the estate tax repeal was not the president's first.
Continuity mistake: Toby and Leo are in Leo's office talking about the friendly fire incident - Leo's glasses are sitting on his desk in front of him. He then picks them up and moves them to the far left. A couple of shots later, he picks them up from the right and puts them on.
Continuity mistake: While Sam and Donna are listening to a TV report that Sam may be heading for Congress, the woman behind him has a phone receiver to her ear, with both hands on the phone. The shot changes and suddenly her right arm is down by her side, but in the next shot it is back in the first position.
Continuity mistake: During the beginning before the opening credits, C.J. is briefing the press corps on the bus. In the outside shot of the bus, C.J. has her left arm resting on a rail, towards the door. When the shot changes to inside, C.J. has her right arm on a rail towards the driver. (00:01:15)