Continuity mistake: When C.J. and Toby discuss and have a snack in Toby's office while the president waits for Chairman Farad's call, at some point C.J. talks while holding the pack of peanut butter crackers in one hand, and one that she is about to eat in the other. Less than a second and a half later, the camera is back on her, but she is now seen holding a bottle of water that was on the table only seconds before.
Continuity mistake: Leo enters the situation room and is told the "planes are on the deck". He watches a video feed as a plane is launched from the USS Lincoln. The S3-B Viking is seen approaching one camera (single vertical tail fin, wing-mounted engines), then from another angle, we see an F-14 Tomcat lifting off (dual tails and fuselage-mounted engines) and moving away from camera. This is supposed to be live video, and it isn't possible two different jets are launching from the same carrier at the same exact moment, so it can only be a bad choice of stock footage by the show's makers.
Continuity mistake: When Kate is in Leo's office with the red folder on her lap, the position of her hands changes depending on the camera angle. Viewed from in front both hands are gripping either end of the folder, from behind her hands are clasped together and rested on top of the folder.