Plot hole: In Season 1, Episodes 5&6, it's mentioned several times that Zoey is already 19 a few weeks before she starts college. Yet in this episode, Charlie points out to Leo and the President later tells Oliver Babbish that Zoey was 17 when she was filling out her enrollment forms for college, therefore a parent had to sign them. These are enrollment forms, not application forms - it's extremely unlikely that they were filled out over a year before she started school.
Factual error: Sam says the "state-of-the-art" oil tanker he recommends can carry 2.2 million gallons of oil and weighs 308,000 tons. The Exxon Valdez could carry over 60 million gallons (1.48 million barrels) and weighed only 211,500 tons. The writers mistakenly swapped 'gallons' for 'barrels' so that this enormous tanker carries very little oil. It would actually carry 2.2 million "barrels", which equals 92 million gallons.
Deliberate mistake: This show is famous / infamous for having many long conversations between characters that are walking the corridors of the West Wing of the White House. In this episode, the chat was long enough that more space was needed to complete the walk, so the actors were instantaneously teleported to a different spot to lengthen the walk. Using http://www.whitehousemuseum.org/special/wwtv.htm as a guide, Pres. Bartlet and Leo leave the Oval Office, pass through the Presidential Secretary's office, turn left, passing between the Roosevelt Room and the Chief of Staff's office. At the end of the Roosevelt room, they turn left through dark wooden doors that are open. Instantly, the actors are at the next junction higher on the map (no wood doors), as if they'd just passed between the Roosevelt room and the Communications Bullpen, and they continue (downward on the map) through the intersection where they original turned (watch for the doors after Leo says "You wouldn't understand").
Audio problem: As Charlie leaves the Oval Office, he pulls the door behind him. When it stops moving, the audio suggests it has been closed fully ("ka-chunk"), yet it's obvious it has not been closed as we can still see the outer office's curtains at the right of the screen, confirmed further when C.J. steps forward and the camera pans right to show the entire door frame area, and the door open quite a bit.
Factual error: In the scene where the Secret Service chief is in the car with Bartlet and he suddenly realizes Bartlet's injured, he yells to the driver to get to GW Hospital and the limo does a screeching U-turn on what appears to be the Arlington Memorial Bridge. At the time they were supposed to be heading from Rosslyn, VA, where the event was, back to the White House. But GW is in DC, not that far from the White House, so although the U-turn looks cool, it doesn't make geographical sense. Also, in that one shot of the outside of the car, it appears to be pouring, while back at the scene of the shooting as well as ahead of them at the hospital entrance, it's not.
Revealing mistake: Oliver Babish's office has windows in a location it can not possibly have them. Jed and Leo are in continuous conversation as they leave the 'normal' West Wing set at the end of a hall (See http://www.whitehousemuseum.org/special/wwtv.htm where the words 'Press Briefing Room' are - that's where they turn to their right). They walk a few steps then turn right again and ahead of them is Babish's office, with windows straight ahead. If this had been a single continuous set, Babish's office would be located in the stair area to the left of the press briefing room, and the windows would offer a view of the hallway that runs between the lower corners of Leo and C.J.'s offices (seen at 3:36), not the outside world.
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.
Revealing mistake: When the Secret Service drags Hoynes out of the White House lobby, they exit through the main entrance, doors that are shown in episodes before and after as leading directly outside. But instead of seeing a convincing night exterior this time, the flashing cameras reveal nothing but a blue studio backdrop is out there.
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.
Factual error: In the situation room, Colonel Chase informs Leo that a CH-47 Seahawk helicopter was dispatched from the USS Monterey. Problem is, the CH-47 is called "Chinook" while the SH-60 is the Seahawk (of which the USS Monterey carries two). See: http://picasaweb.google.com/agbeko.Dzamesi/Aircraft/photo5029495094968996146 for photo of an SH-60B Seahawk landing on the USS Monterey.
Plot hole: In order to allow time for a lengthy scene conversing while walking, actor John Spencer is sent on a ridiculous course through the West Wing. See the floor plan at http://www.whitehousemuseum.org/west-wing/west-wing-TV.jpg to follow along. He's first spotted leaving Margaret's area (blank space located just up and left of his "Chief of Staff" office on the plan). The handheld camera is in the Roosevelt room at this point. He turns right, traveling between his office and the Roosevelt room, meeting Donna along this hall. They make two slight left turns, then a hard left, entering the Roosevelt room (at the top/right corner's diagonal door). They walk the length of the room, turn left (down) and Leo drops some of the paperwork he carries onto the end of the table. They then exit the room (bottom left door) which is right outside the doorway where Leo started the scene. Leo isn't wandering. He's quite deliberate in his choices, yet if he'd simply walked straight ahead 6 or so steps from where he started, he'd have been where he dropped the papers.
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.
Audio problem: During the blackout, Donna and Josh sit together. The scene begins with the camera looking out the window, panning right to reveal Donna as we hear her finish saying, "You know what I'm surprised about?". But her mouth isn't moving at all until she begins her next sentence, and it's visible when we're hearing "about".
Factual error: In the scene when Leo tells president Bartlett that he is attending the concert, they refer to the Icelandic ambassador as a man. Leo says his name is Vigdis Olafsdottir, when is fact it is a woman's name that means Vigdis daughter of Olaf. During the concert the ambassador is portrayed by a man. They "borrowed" this name from Tom Clancy's novel Red Storm Rising, by the way.
Other mistake: In a scene with Leo and the President, Toby confronts them about the fact that there was no clear person in charge while the President was in hospital after being shot. He references the shooting as taking place 'last May'. However, in an earlier episode, 'The Midterms', there is a title card that states the date as August 14th and in the scene that follows there is discussion about the staff job approval in which CJ states, 'A week ago the job approval is at 51, we got shot at and its at 81.' This would mean that the shooting took place in August not May.