When Molly confesses to Kate, the phone is ringing. When Kate watches the "hidden camera" replay, we do not hear the phone.
When Bud is driving Richard Petty's race car, he asks Molly to get a photo of him with his chin out, so he "looks like a hero." He moves the the helmet-microphone off of his chin. In the next shot, it's back.
Election Day is Tuesday. The next day, Bud is told he is certified to re-vote in 10 days, which would be a week from Saturday (Wednesday + 10 days). The next week, Tuesday is "Take your Father to School Day." That day that Bud visits the President one last time. That night, he crams for the debate, which is the next evening, Wednesday. Then he votes the day after that, Thursday, which is actually 8 days later.
When the media first show up at Bud's trailer, he looks out through a window on the right side (from the inside the way he is facing) of the door to his trailer and pulls down the left blind. When the camera changes to an outside view of the trailer, he pulls down the same blind, and the one beside it is already down, as though the sides changed positions.
When Bud and the President are talking on Air Force One one of the glasses disappears from the table and in the next shot both glasses are there again.
Air Force One is never allowed to sit idle on a runway with the President on board.
Schools are closed on election day but Molly's school is clearly shown to be in session that day.
In New Mexico bars are closed while polls are open - 7 am to 7 pm. Bud would have to be drinking with friends not in a bar.
Bud complains that Molly registering him to vote can get him picked for jury duty now. Merely getting a driver's license qualifies people for jury duty.
The two Marines in the hallway are wearing their covers (hat), but covers are only worn indoors if you are wearing a firearm. The two Marines are not wearing a firearm per USMC Drill & Ceremonies Manual MCO P5060.20.
The film's plot is not impossible under the United States Constitution. Regardless of the circumstances relating to a particular state's electoral votes, if following a presidential election no candidate has a majority of the Electoral College votes the election is decided by the House of Representatives. However, the electors don't vote until December 15. Before the electoral college vote, states may take steps to ensure that their votes are being recorded correctly, which may entail a recount or door-to-door campaigning, as provided by state law. Federal law provides such votes will have safe haven if completed by December 12 using procedures that were in place as of election day.
When Bud wonders why so many people are outside his trailer, he tells Molly to turn on the TV. The screen shows Fox News Channel, but the TV has rabbit ears. Satellite TV subscribers sometimes need an antenna to view local channels.
A large number of packages are delivered to Bud by a UPS driver, but in the next scene, letters with USPS stamps are shown. While UPS does not deliver First Class mail, the two scenes do not happen in the same setting; they only show that Bud is getting a lot of packages and mail, via different couriers.
The power pole outside Bud's trailer has there is no power meter, even though wires go to the trailer.
When Bud gets on stage at the party with Mr. Greenleaf, the woman directly behind Molly taps her on the head to signal when she should depart the scene.
When Bud and his daughter are first riding in their pick-up truck, the transmission is clearly in park.
When Bud walks out of the bar drunk, he is standing normally, but the VOTE TODAY sign is so low that he bangs his head in to the sign and falls down. It seems very unlikely that no one else walking down the sidewalk wouldn't have already complained that the sign was blocking the sidewalk.
Texico, NM is near the Texas/New Mexico border, so you would not have seen the mountain range in the background.
Ex-Felons in New Mexico are permanently banned from voting. During the movie Bud is reminded by his daughter that he has one strike left, meaning he was a two time felon. This would make his vote illegal.
When the election officials visit Bud and Molly for the second time, Bud asks if they can move the news people further back, because they did't get much sleep the night before. One of the election officials turns and signals the agent with ear piece standing behind them to go sort it out. As he walks off, he lifts his left sleeve to speak into the microphone, then quickly switches to his right sleeve once he realizes his mistake.