President of the United States

The President of the United States of America was the political leader of that North American nation, elected — according to American Peri Brown — by ordinary citizens once every four years. (AUDIO: The Eye of the Scorpion)

The president's traditional residence was the White House in Washington, DC. Arguably the most famous room in the White House was the Oval Office, the president's symbolic seat of power. By at least 1969, the president was regarded as one of the most powerful people on Earth. (TV: Day of the Moon)

Indeed, it was plausible to infer the long-lasting impact of the office from the fact that the White House was the official residence for the President of Earth from the 26th century (AUDIO: Scorpius) until at least 4041, (COMIC: Return of the Klytode) long after the United States had become part of a world government.

In 2011, Dr Samantha Madigan told Clyde Langer that the famous Native American curse, the Curse of Tippecanoe, was supposedly placed on the US Presidents. (TV: The Curse of Clyde Langer)

List of presidents
Several American presidents were known to the Doctor and his friends. However, information on most of these figures — even basic details such as their terms of office — was sketchy, as direct contact with American presidents was unusual. Because of the paucity of data, it was possible to list the presidents accurately only in simple alphabetic order.
 * James Buchanan (PROSE: Blood and Hope)
 * George H. W. Bush (PROSE: Interference)
 * Carrol (PROSE: Rennigan's Record)
 * Jimmy Carter (PROSE: Option Lock, Interference)
 * Bill Clinton (PROSE: Placebo Effect)
 * Lola Denison (PROSE: Head of State) - Sworn in as president following the assassination of Matt Nelson.
 * Tom Dering (PROSE: Option Lock, Millennium Shock)
 * Dwight D. Eisenhower (TV: Spearhead from Space, Dreamland)
 * Gerald Ford (PROSE: The Assassin's Story)
 * Herbert Hoover (TV: Spearhead from Space, Daleks in Manhattan)
 * Thomas Jefferson (AUDIO: Urgent Calls)
 * Lyndon Baines Johnson (TV: Spearhead from Space)
 * John F. Kennedy (TV: Spearhead from Space, Remembrance of the Daleks, Silver Nemesis, Rose, Tooth and Claw, PROSE: Who Killed Kennedy, Shroud of Sorrow)
 * Abraham Lincoln (TV: The Chase, Spearhead from Space; PROSE: Blood and Hope)
 * (TV: The End of Time) - Briefly, when he turned the entire population of Earth, including Barack Obama, into a copy of himself.
 * Felix Mather (PROSE: Trading Futures)
 * William McKinley (PROSE: Byzantium!)
 * Richard Nixon (TV: Spearhead from Space, The Impossible Astronaut / Day of the Moon)
 * Matt Nelson (PROSE: Head of State) - Elected but assassinated immediately after inauguration.
 * Chuck Norris (PROSE: Cat's Cradle: Warhead, PROSE: Interference)
 * Barack Obama (COMIC: Ghosts of the Northern Line, TV: The End of Time)
 * Ronald Reagan (PROSE: Option Lock, Interference)
 * Franklin Delano Roosevelt (PROSE: Endgame)
 * Theodore Roosevelt (TV: Spearhead from Space)
 * Bruce Springsteen (PROSE: Eternity Weeps, PROSE: Interference)
 * Harry S. Truman (PROSE: Endgame)
 * Unnamed 1 (TV: Extremis) - In a simulated world.
 * Unnamed 2 (TV: The Pyramid at the End of the World)
 * George Washington (TV: Spearhead from Space)
 * Arthur Coleman Winters (TV: The Sound of Drums) - Referred to variously as "President" and "President-elect."
 * Courtney Woods (TV: Kill the Moon) - The Twelfth Doctor told Clara Oswald that she would be an American President in her future.

Timing
The Doctor had some rough idea as to the dates certain presidents served. He could place Abraham Lincoln in the early-to-mid 1860s, as the Fifth Doctor prevented his assassination just days before he was shot by John Wilkes Booth in 1865. He likely would have been able to place James Buchanan as Lincoln's predecessor, since Buchanan was widely seen as a contrast to Lincoln, and was a topic of conversation for people whom the Fifth Doctor knew. (PROSE: Blood and Hope) The Sixth Doctor had detailed historical knowledge of that assassination when he and Evelyn Smythe travelled to Washington DC just before Lincoln lost his life. (AUDIO: Assassin in the Limelight) Similarly, the Ninth Doctor was in Dallas when Kennedy was killed; clearly he knew the time of the Kennedy assassination. (TV: Rose)

The Eighth Doctor once gave a time-ordered list of presidents, saying that if one started in the 1970s with Jimmy Carter, the list would continue: Ronald Reagan, George H. W. Bush, Bill Clinton, Tom Dering, Bruce Springsteen and Norris. (PROSE: Interference) Certainly, the Eighth Doctor would've been able to place Tom Dering at the end of the 1990s, since he and Samantha Jones spent a lot of time with that president investigating the Station Nine incident and other related events. (PROSE: Option Lock)

The Tenth Doctor spouted textbook knowledge of Herbert Hoover, accurately giving Hoover's number in the order of presidents, as well as his inaugural year. (TV: Daleks in Manhattan) In 1958, he referenced Eisenhower's name when asking if Colonel Stark knew about the Dreamland base, also known as Area 51, showing the Doctor knew he was President at that time. (TV: Dreamland) By contrast, the Eleventh Doctor seemed fuzzier than River Song on who had been president in 1969 but soon discovered that it was Richard Nixon who was in office at that time. (TV: The Impossible Astronaut / Day of the Moon)

The Tenth Doctor also witnessed Arthur Coleman Winters' death on board the Valiant, (TV: The Sound of Drums) as well as Barack Obama's transformation into the Master. (TV: The End of Time)

Following the successful deterrence of a Quark invasion, the Second Doctor was advanced as a possible candidate for president, in what would have been the 1972 elections. (COMIC: Martha the Mechanical Housemaid)

Captain Lundvik stated that a woman was President in 2049. The Twelfth Doctor later said Courtney Woods would be President sometime in her future. (TV: Kill the Moon)

After discovering that fragmentary historical records available in the year 4000 erroneously stated that the television presenter Bruce Forsyth was the Prime Minister of the United Kingdom in 1977, Charlotte Willis jokingly asked the Fourth Doctor if they thought that Gene Kelly was the U.S. President. (AUDIO: The Foe from the Future)

Alternate histories
There were a few people who were presidents in alternate timelines, such as Benjamin Franklin. (AUDIO: Seasons of Fear, Neverland)

On a Shadow Earth in 2017, created by the Monks, the American president was sent a translation of the Veritas document. Upon reading the document and learning that he was part of a fake Earth, the President committed suicide in the Oval Office. (TV: Extremis)

Limiting term length
Exact term length of individual presidents is pretty fuzzy, perhaps because it is irrelevant to most narratives where presidents appear. However, Peri does nail down the generic term to four years when Erimem asks her how the Americans' leaders are chosen in The Eye of the Scorpion.

The wilderness years
One major problem area for presidential terms is in the novels which appeared during the 1990s and early 2000s. Here, a variety of not-particularly-reconcilable problems ensue. Not only did some of these "prose presidents" never serve in real life, but they do pretty massively conflict with each other. Most novels seem to agree that presidential order conforms to real history through Bill Clinton's first term, but thereafter, there are a variety of other people — and rather too many of them to all be serving four year terms. It is completely impossible to fit all the presidents from Clinton to Obama posited by RTD and "Wilderness Years" authors into any kind of sensible timeline.

The Winters problem
One of the more famous presidential conundrums is that caused by Russell T Davies calling Arthur Coleman Winters the "President-elect" during The Sound of Drums.

While there are many differences between the real world and the DWU, such a statement is particularly difficult to understand, just within the context of DWU narratives alone. It's hard to see how he could, in the spring/summer in which Drums appears to occur, be the President-elect, when Day of the Moon gives a very clear indication that Richard Nixon's presidency began about six months prior to the Moon landing, which is positively dated to July 1969. He also seems to have been elected after another president mentioned in The Christmas Invasion, but before Barack Obama, who is actually seen and heard in The End of Time. The timing of all this is simply impossible to figure out — not to mention the fact that Trinity Wells says in Drums that Winters arrived in the UK on Air Force One — which wouldn't be the case if he were merely the President-Elect. Eventually, in a commentary, Davies admitted that he had simply been wrong to call Winters the "President-elect" — which makes that an ignorable production error.

Donald Trump
In the real world, Donald Trump won the 2016 presidential election, and was inaugurated in 2017. Prior to the election, he was established as a DWU politician in the year 2016 in the novel What She Does Next Will Astound You. However, in the Shadow World 2017, made by the Monks to resemble the real world almost perfectly, an unnamed president was a dark haired individual who did not have much physical resemblance to Trump. According to Moffat, Extremis was written before but filmed after the 2016 election.

However, Trump is implied — though not explicitly stated in dialogue — to be the current sitting US President in the following episode, The Pyramid at the End of the World. Bill notes that the recently elected President is "orange", and says that she wouldn't have voted for him. The final episode of the trilogy, The Lie of the Land, features an image of Trump clearly visible on one of the screens inside the room that houses their propaganda machine, but not explicitly shown as the president.

Invalid sources
An unnamed President appeared in the invalid story Death Comes to Time, based upon then-current President.