At one point in the movie, two characters watch the political commentary show "Hardball" right after waking up in the morning. "Hardball" actually airs twice in the evening, at 5:00PM ET live and 7:00PM ET in rebroadcast. It never airs during the morning.
Ryan Gosling's character mistakenly refers to the two lecterns on the stage as podiums when he asks: "Are we going to put risers under these podiums?" A podium is a platform on which the speaker and lectern stand. A lectern is not a podium.
George Clooney and his wife are having a conversation in the campaign bus, at night somewhere near Cincinnati. But an exterior shot shows the bus pass a "Lansing" sign with the Michigan state route (diamond) symbol.
With the Ohio primary on the horizon, only two Democratic candidates remain and both are vying for the endorsement of North Carolina Senator Franklin Thompson. In the film, an endorsement from Thompson is dealt with as swinging 356 pledged delegates. However, in 2008, North Carolina carried with it only 134 delegates (115 pledged delegates, 19 superdelegates). Furthermore, in the Democratic nominating process, superdelegates cannot swing delegates. Of the 115 pledged delegates, they are proportionally awarded based on primary results.
The goof items below may give away important plot points.
Ryan Gosling's character is shown shaving in the bathroom as he gets ready to go somewhere, in the next scene, supposedly right after he's shaved, he's back looking like he has at least 1-2 days of beard growth (which is the character's usual look).
At the press conference for Molly's death, Morris says that Cincinnati police are investigating the incident. However, her death occurred at a hotel in Kentucky, which would put her case outside of Cincinnati police jurisdiction.
Ryan Gosling is driving Evan Rachel Wood in a southern direction across the historic Roebling Bridge (who also built the Brooklyn Bridge) to Covington Kentucky and ends up at a Cincinnati Abortion clinic that would be on the northern side of the Ohio River.
At the church funeral for Molly Stearns, whose family is portrayed as being devout Catholics, her casket is parallel with the altar and it is not covered with a pall.
A funeral in a Catholic church for non-clergy would have the casket positioned so that the feet would enter first and the casket would remain feet end pointing towards the altar (i.e. the deceased would be facing the altar), and the casket would be covered with a pall - a type of cloth that covers the casket.