Dork Horse Candidate

It's a staple of teen dramas: the Alpha Bitch is running unopposed for the presidency of the Absurdly Powerful Student Council. She gloats to the unpopular kids about her continued reign, until one of them says, "That's it! You've ruled this school for too long! I'm running against you!" The Dork Horse Candidate is born.

The Dork Horse Candidate is not just an underdog, but someone completely unsuited for politics. He lacks intelligence, charisma, popularity and administrative skill. There's usually a debate between the candidates, in which the dork horse is made to look like an even worse option.

The candidate can be most any character, but typically is not one of The Libby's usual adversaries, such as the Cool Loser or The Snark Knight. However, these are usually the people who tell the Dork Horse Candidate that he has no chance of winning.

The candidate may assemble a Ragtag Bunch of Misfits advisory team. Each kid will have a task for which he or she is poorly suited. If someone is doing opinion polls, it will be Shrinking Violet or The Unintelligible.

The Dork Horse Candidate almost always wins, usually by one vote. Either he gives a Rousing Speech, or some Deus Ex Machina comes along to nullify his electoral disadvantage. See also Dark Horse Victory.

Please, no real life examples.

Examples of Dork Horse Candidate include:

Anime

Urusei Yatsura - In Mendo's introductory episode/chapter, he runs for class president on the platform of draconian punishments for misbehavior. Except not for the girls. Ataru is pressed into running against him by the boys, leading to a tied vote. To resolve that, they duel and Ataru wins, making Mendo the vice president.
Ojamajo Doremi, with the random classmate of the week running against Tamaki Reika.
Azumanga Daioh. In the manga, the class only has one person willing to run for president, Genki Girl Tomo. No-one in class is really eager to vote for her, either. The teacher throws the class's most popular student up against her anyway. Chiyo wins 30-2, which does beg the question of who else would vote for Tomo. Chiyo, who didn't want the job anyway. At least it beats how the class president was chosen the previous semester - Yukari announced they needed one, waited five seconds for nominations and then declared a random guy in the front row the winner.
Toradora! - This trope gets a twist: Taiga runs for the position of student council president against Yuusaku in an attempt to motivate him to run for president himself. She almost would have won too, being the only candidate, despite threatening the student body with lots of misery when she'd hold the office.
This was parodied in To LOVE-Ru, which had Lala going up against Yui. The winner? Haruna, even though she isn't running. Because Yui's a hardass, and Lala obviously has no clue what she's doing.
Subverted in Kamichu! The under-confident goddess Yurie is pressed into running against a brilliant but obnoxious student for middle school student president. She wins in the usual fashion of the trope... then celebrates with a wave of crazy alterations to the school, uses up all her energy in the process, and passes out for a week. With Yurie unable to serve, the presidency passes to the obnoxious guy, who's furious he has to deal with the fiasco Yurie left him.

Film

Napoleon Dynamite - A definitive Dork Horse Candidate is Pedro.
Head of State had an attempt to throw a presidential election by a political party go horribly right.
In Welcome To Mooseport, a feckless handyman (Ray Romano) campaigns against a retired U.S. president (Gene Hackman) to be mayor of a small town.
While he was appointed rather than elected, Jimmy Stewart's breathtakingly naive character in the 1939 classic Mr. Smith Goes To Washington was the original Dork Horse Candidate.
Revenge of the Nerds is based around this, with the titular nerds wanting to take over the school council and get vengeance on their jock nemeses.
Election - The class-presidential campaign of Tammy Metzler. Her sole campaign promise was to dismantle student government once elected "So none of us has to sit through one of these stupid assemblies ever again!". If it wasn't for Adult Meddling, she would have won in a landslide.

Live Action TV

Dinosaurs had the Bumbling Dad run against his Corrupt Corporate Executive boss; it ended in him giving a speech about how neither of them were suited, and everyone decided to vote for the news reporter (a not-veiled-at-all pastiche of Edward R. Murrow) who had been commentating on the whole thing.
An episode of Saved by the Bell has Screech (Dustin Diamond) win the Miss Bayside pageant.
Heroes - Claire Bennet, despite being a pretty, popular cheerleader, still manages to win Homecoming Queen by presenting an underdog image to the school's geeks.
Subverted/Parodied in Arrested Development, where George Michael runs against Steve Holt. Steve Holt drops out of the race, and George Michael still only gets 3% of the vote. The Indian kid wins.
Buffy the Vampire Slayer ran against Cordelia for prom queen, just to prove that she could. The election eventually ended in a tie between the other two candidates.
Popular - April actually won after the more popular candidates dropped out.
In an episode of California Dreams, Jake, the resident semi-loner bad-boy ends up in the running and after almost dropping out wins the thing by singing a song called 'Leather and loose'.
Ned's Declassified School Survival Guide - Played with in the fact that Ned has to be forced to run and his attempts to not get elected backfire hilariously. They end up getting him a fair percentage of the votes. And yet, somehow, the weasel which is nominated every year as a joke ends up winning.

Newspaper Comics

A Peanuts story arc from October 1964 has Linus running for class president, with Charlie Brown as his vice-president. At first Linus is reluctant to run, then he discovers a talent for public speaking, then he blows it by giving a speech about the Great Pumpkin. Read it here. The storyline was re-hashed for a TV special, You're Not Elected, Charlie Brown.

Video Games

An early mission in Bully involves Earnest, de-facto leader of the Nerd clique, running for class president, and hiring Jimmy (the protagonist) to protect him from being harassed while he gives a speech.

Western Animation

In an episode of The Fairly OddParents, Timmy Turner runs for class president against popular kids Tad and Chad. Timmy wins when every other kid in school is sick on election day from eating cake.
Tucker running up Jerk Jock Dash Baxter in Danny Phantom.
In the Family Guy episode "Running Mates," Peter runs against Lois for school board president. He wins after publicizing a scandalous photo of her.
In the classic Looney Tunes cartoon, Ballot Box Bunny, Bugs Bunny and Yosemite Sam engage in the usual hijinks over a mayoral election, only to have a very literal "Dark Horse" win the election and become "Mare."
Parodied in The Oblongs, "Disfigured Debbie." The Ragtag Bunch of Misfits run one of their own against the Alpha Bitch. She crushes their Dork Horse Candidate in a landslide, then the whole school throws a grand celebration of her victory.
Foster's Home for Imaginary Friends - Frankie Bloo runs against Mr. Herriman . He was obviously not suited for the position as President of the house.
The Powerpuff Girls - Fuzzy Lumpkins yelling "shut up" at the campaigning Mayor—and then going on to win despite lazing off back at his house as he usually does.
In The Simpsons, Bart Simpson runs for class president against Martin Prince. Everyone in the class prefers Bart, but he loses because he throws a preemptive victory party, meaning the only people who bother to vote are Martin and his equally geeky friend. Later, Homer cheers up Bart by convincing him that he's better off not being class president, because it's just extra work for no benefit.
Used in Recess, where Gretchen (the smart one) competes against Vince (the popular one) for Fourth Grade President. Gretchen wins by one vote - Vince's. The twist? Vince and Gretchen are actually good friends.

Webcomics

Penny and Aggie, which even had two of these in Aggie and Duane being pounded on by charismatic jock-type Stan. Eventually Duane only wins because Stan decides he's already popular enough and endorses him.
In Sluggy Freelance, in the "Meanwhile in the Dimension of Pain" guest stories, the demons of said dimension hold an election to choose a new Demon Lord after Lord Horribus is banished. His scheming little brother Terribus runs for office, and his only opponent is the resident idiot Reakk. The demons are unenthusiasti about voting for either. In the end, Terribus wins through a Genre Savvy Batman Gambit. The election is held by tearing wings off butterflies, but the butterflies all manage to fly into a beam of light that burns the demons. Terribus arranges for Reakk to end up briefly in the beam and retrieve a butterfly, allowing him to cast the only vote, because he knows Reakk is such an idiot he will accidentally tear off the wrong wing and vote for Terribus.

Literature

In the Gordon Korman book Don't Care High, two friends at the most boring, lackluster high school in the city, completely as a gag, select a random nobody student to promote as class president... and due to snowballing events he becomes an icon of cool to the entire student body, much to his bewilderment. The hitch of the story is, from beginning to end, the kid they pick is such a nondescript cipher that they never figure out anything at all about him. Not his real address, not his phone number, not his pastimes, they never see his home or his family, all his previous addresses and schools don't or no longer exist... they even go so far as to break into his confidential records and find literally nothing in it. And at the end of the story the kid simply disappears -- "moved to another town"—and his forwarding address is nonexistent as well. A cipher from beginning to end.
In Young Adult Novel by Daniel Pinkwater, when the Wild Dada Ducks discover that Kevin Shapiro is the name of an actual student at their high school, not just a character in their stories, they decide to run a publicity campaign for him, unaware that the student council election is happening at the same time. Kevin wins the election by a landslide despite not even being on the ballot. The school demands a new vote, whereupon Kevin gives a speech telling the students to vote for someone else since he doesn't want to be on the stupid council anyway—which is greeted with thunderous applause. Of course they elect him anyway.