The Treaty - S4-E7
Revealing mistake: Tom is talking on the phone in Ron's office. When he turns the phone at an angle the call home screen that has the end button, the speaker button, etc. turns to its side, which means it was a picture - he wasn't actually calling anyone. (00:02:25)
The Treaty - S4-E7
Factual error: At the UN conference, 'England' is shown as a member of the Security Council. England sits on both the UN and the Security Council as part of the 'United Kingdom' - not as a stand-alone country. UN nerds Leslie and Ben would have known this.
Campaign Ad - S4-E12
Continuity mistake: When Chris is talking to Ron in his office, he accidentally hits the gun on the corner of the desk causing it to rotate. When the next shot is taken, the gun has returned to its normal position. (00:04:25)
Continuity mistake: When Ben and Leslie approach the commissioner about the recount, there are two guys sitting down behind Jen. The camera follows the commissioner leaving the room and then momentarily shows Leslie and Ben. As Jen is lying out on the table the two guys have now disappeared. (00:13:00)