Starting in a small section of the near South, both U.S. Army Captain James West and U.S. Marshal Artemus Gordon hunt for Confederate General "Bloodbath" McGrath, who is wanted for mass murder. It points back to when McGrath ordered a massacre in a settlement called New Liberty, where many of the freed slaves were murdered, including West's biological parents. The search leads to a brothel where the two try (unsuccessfully) to arrest him. It leads to a huge brawl and a cart of nytroglycerin crashing into the building that starts a fire. Both West and Gordon, the latter dressed as a woman, escape.
The film opens with newsreel footage, including the farewell address in 1961 of outgoing President Dwight D. Eisenhower, warning about the build-up of the "military-industrial complex". This is followed by a summary of John F. Kennedy's years as president, emphasizing the events that, in Stone's thesis, would lead to his assassination. This builds to a reconstruction of the assassination on November 22, 1963. New Orleans District Attorney Jim Garrison subsequently learns about potential links to the assassination in New Orleans. Garrison and his team investigate several possible conspirators, including private pilot David Ferrie, but are forced to let them go after their investigation is publicly rebuked by the federal government. Kennedy's suspected assassin Lee Harvey Oswald is killed by Jack Ruby, and Garrison closes the investigation.
President of the United States James Sawyer (Jamie Foxx) is generating controversy over a proposed peace treaty between the allied nations to remove military forces from the Middle East. John Cale (Channing Tatum) is a US Capitol Police officer assigned to Speaker of the House Eli Raphelson (Richard Jenkins) after he saved his nephew's life during a tour in Afghanistan. He is divorced and struggling to develop a better relationship with his daughter Emily (Joey King), who has a strong enthusiasm for politics. He hopes to impress her by getting a job with the Secret Service protecting the President, but his hopes are dashed when the interview is conducted by Carol Finnerty (Maggie Gyllenhaal), a former college acquaintance of his who believes him to be unqualified due to a lack of follow-through and respect for authority. To avoid admitting the truth to Emily, Cale takes her on a tour of the White House.
Frank Drebin (Leslie Nielsen) is honored at the White House, where President George H. W. Bush (John Roarke) announces that he will base his recommendation for the country's energy program on Dr. Albert Meinheimer's (Richard Griffiths) advice at the National Press Club dinner the following week. The heads of the coal and oil (fossil fuel) and nuclear industries are apparently distressed by this fact, as Dr. Meinheimer is an advocate for renewable energy. Jane Spencer (Priscilla Presley), now working for Dr. Meinheimer, is working late at his research institute, crying about Frank. She spots a man in a red van. A maintenance worker, emptying out garbage cans, discovers a clock with dynamite attached and takes it to the security guards, accidentally triggering it. The next morning, Frank reacquaints himself with Jane as he interviews her about the explosion. He is shown around the institute and meets Jane's boyfriend, Hexagon Oil executive Quentin Hapsburg (Robert Goulet), of whom he becomes exceedingly jealous. Frank's boss, Ed Hocken (George Kennedy), finds him at a lonely blues bar. Meanwhile, at a meeting of the "energy" industry leaders, Hapsburg reveals that he has kidnapped Dr. Meinheimer and found an exact double for him, Earl Hacker, who will give their recommendation to the President endorsing fossil and nuclear fuels.
Prior to the destruction of Krypton, the criminals General Zod (Terence Stamp), Ursa (Sarah Douglas) and Non (Jack O'Halloran) are sentenced to banishment into the Phantom Zone for insurrection and murder, amongst other crimes.
The "Minutemen", a team of costumed crime fighters, was formed in 1939 in response to a rise in costumed gangs and criminals; the "Watchmen" was similarly formed decades later. Their existence has dramatically affected world events: in particular, Doctor Manhattan's superpowers help the United States win the Vietnam War, resulting in President Richard Nixon being reelected. Doctor Manhattan gives the West a strategic advantage over the Soviet Union, which by the 1980s threatens to escalate the Cold War into a nuclear war. During that time, growing anti-vigilante sentiment in the country leads to masked crime-fighters being outlawed. While many of the heroes retire, Doctor Manhattan and the Comedian operate as government-sanctioned agents, and Rorschach continues to operate outside the law.
Former Special Forces soldier Mike Banning (Gerard Butler) is the lead U.S. Secret Service agent assigned to head the U.S. Presidential detail. Banning maintains a personal, friendly relationship with President Benjamin Asher (Aaron Eckhart), First Lady Margaret (Ashley Judd) and their son Connor (Finley Jacobsen). During a snowy Christmas evening drive from Camp David to a campaign fundraiser, the car transporting the First Family crashes; Banning saves Asher, but Margaret dies.
In 1818, Abraham Lincoln (Benjamin Walker) lives in Indiana with his parents, Nancy (Robin McLeavy) and Thomas (Joseph Mawle), who works at a plantation owned by Jack Barts (Marton Csokas). There, Lincoln intervenes when he sees his friend, a young African American boy, William Johnson (Anthony Mackie) being beaten by a slaver. Because of his son's actions, Thomas is fired. That night, Lincoln sees Barts break into his house and attack his mother. Nancy falls ill the following day, and dies shortly afterwards. Thomas tells Lincoln that Barts poisoned her, but asks that he promise not try to avenge her death.
In Kentucky, a family watches an enormous horde of cattle running past their home, having caught fire, and a flying saucer leaving Earth. The ship explodes before it returns to Mars, and hundreds of other Martian ships leave Mars and head towards Earth.
Dave Kovic (Kline) runs a temporary employment agency in Georgetown, Washington, D.C., and has a side job impersonating President Bill Mitchell (Kline). He is requested by Secret Service agent Duane Stevensen (Rhames) to make an appearance as the President at a hotel. Dave assumes it is a matter of security, but it is really to cover up Mitchell's extramarital affair with a White House staffer (Laura Linney).
Mays Gilliam is an alderman of the 9th Ward in Washington D.C.. After being fired from his post and dumped by his girlfriend, Kim, Mays is surprisingly chosen as the party candidate for the presidency (after his party's original presidential and vice-presidential nominees die when their two separate planes crash into each other) to run against sitting vice-president Brian Lewis. Assuming the election was already lost, the party decided to pick a likable but unwinnable minority candidate to improve their chances in the next presidential election. At first, Mays feels he will not be able to succeed as President because he would be representing the entire African-American populace, and does not want to do anything to mess it up. However, Mays begins to rise in the polls after his brother persuades him to speak out for what he believes. He begins to talk about issues such as welfare, money, society, etc. After Lewis runs a series of attack ads including one saying Mays supports cancer, Mays begins to fight back using what he claimed was "kissing" his opponent (taken from Bugs Bunny-Elmer Fudd cartoons). A part of this strategy includes dubbing a videotape of Osama bin Laden saying he hates America but loves Brian Lewis. This strategy gains Mays even more points in the polls. As voting day draws closer, Mays eventually learns the reason why he was chosen as the party candidate, and fires some disloyal campaign operatives (although they reconciled with him afterwards), as well as choosing his brother as his running mate. He later has a debate with his opponent in which he manages to win the crowd over by speaking truth about the American life. Finally, Mays ends up winning the election and the presidency. The film ends with a shot of Mount Rushmore with Mays Gilliam's head added; complete with bling.
The film opens with George W. Bush (Josh Brolin), dreaming of being a baseball player and is in the stadium with a empty crowd cheering for him. In 1966, Bush endures an alcohol-fueled initiation by his fellow Yale University students as a Delta Kappa Epsilon pledge. During the hazing, Bush successfully recalls the names and nicknames of many of the fraternity members, and states that his family's political legacy is one in which he has no interest. A little later, after Bush is jailed in New Jersey for rowdiness following a football game, his father, George H. W. Bush (James Cromwell), states that he will help Bush, but for the last time. Following his graduation from Yale, Bush takes a job at an oil patch back in his home state of Texas, but he quits after only a few weeks. In 1972, "Junior" reveals his real aspirations in a father-son talk: working in professional baseball, in some capacity. Soon afterwards, Bush is accepted into Harvard Business School with the help of his father. That night after drinking heavily, Bush crashes his car into his family estate and challenges his father to a fistfight. His brother, Jeb (Jason Ritter) intervenes and stops the fight.
Betsy Jobs (Kirsten Dunst) and Arlene Lorenzo (Michelle Williams) are two sweet-natured but somewhat ditzy teenage girls living in Washington D.C. in the early 1970s. Betsy comes from a wealthy family in the Georgetown area, while Arlene lives with her widowed mother in an apartment in the Watergate building. One night, on a quest to mail a letter to enter a contest to win a date with teen idol singer Bobby Sherman, the two girls sneak out of Arlene's home, at the same time as the Watergate break-in. They manage to enter and leave through the parking garage by taping the latch of a door, accidentally causing the break-in to be discovered. They are seen by G. Gordon Liddy (Harry Shearer), who they believe to be committing a jewel robbery; they panic and run away. The security guard, startled by the taped door, calls the police, who immediately arrest the burglars.
In a restroom in the White House in Washington, D.C., a janitor finds White House secretary Carla Town (Mary Moore) dead. Metropolitan Police homicide Detective Harlan Regis (Wesley Snipes), whose apartment house is awaiting demolition in favor of a parking lot, is put on the case. At the White House, Regis is introduced to U.S. Secret Service Director Nick Spikings (Daniel Benzali), U.S. National Security Advisor Alvin Jordan (Alan Alda) and Secret Service agent Nina Chance (Diane Lane). Spikings assigns Chance, a former Olympic gold-class sharpshooter, to keep an eye on Regis.