In the age of social media and Youtube, these moments were given greater reach than had ever been seen in any presidential race. Statements were isolated, shared and analysed, and parody was never far behind.
From the inspirational to the ridiculous, nothing went unnoticed.
Perry and Cain
The Republican primary field was shaken up in August 2011 by Rick Perry's much-vaunted entry into the race. Trumpeted by red-blooded conservatives as the real deal, the Texas governor turned out not to be ready for primetime.
In his most embarrassing moment, he struggled during a live debate to remember the third government agency he wanted to eliminate. Fumbling for an agonising 45 seconds, he finally gave up, concluding apologetically: "The third one, I can't, oops."
If Perry was the great disappointment, the big surprise was Herman Cain, who peppered lively interviews and debate performances with numerous mentions of his wildly simple 9-9-9 tax plan. The former CEO of Godfather's Pizza led opinion polls for almost a month before his campaign was torpedoed by a string of sexual harassment allegations in late October. Asked in a TV interview if he was ready to avoid gaffes, Cain famously replied: "When they ask me who is the president of Ubeki-beki-beki-beki-stan-stan, I'm going to say 'you know, I don't know'."
The way they roll
During the primaries, Romney, who was born into privilege and earned an estimated $250-million fortune at Bain Capital, provided plenty of ammunition to critics keen to paint him as out-of-touch with the average voter. In a December debate with Perry, who routinely managed to get under his skin, Romney offered the Texas governor a $10 000 bet during an argument over health care. $1 would have sufficed. Romney came unstuck again in February while trying to woo voters in his native Michigan, telling a crowd that his wife Ann "drives a couple of Cadillacs".
The Obama campaign used these and other gaffes such as: "I have some great friends who are Nascar team owners"; "Corporations are people, my friend"; and "I like being able to fire people" in later attack ads. MC 'Bama Obama made a major gaffe on July 13 during a campaign speech in Virginia when he said "You didn't build that", when trying to explain that successful businesses rely on public infrastructure. Conservatives seized on it as an insulting defense of "Big Government" and used it remorselessly in later attack ads. And of course, the internet did not disappoint, and this masterpiece soon appeared.
Obama's good friend, Bill Clinton
The star turn at the Democratic convention in early September came from an old master: Bill Clinton. Clinton set about dismantling Romney's attacks on the economy piece by piece, telling American voters no president could have turned around the mess Obama inherited in just four years. "Conditions are improving and if you'll renew the president's contract you will feel it. I believe that with all my heart," he implored.
Polls after the convention showed Obama opening up a clear lead, with Clinton getting a lot of the credit.
We are the 47% (and now we don't like you)
Obama's post-convention bounce was boosted by the most significant Romney gaffe of the campaign. It came via a secretly-recorded video from a May fundraiser and the content was political dynamite. In the tape, released on September 17, Romney was heard telling an elite crowd that 47% of the country were dependent on government, believe that they are victims and would vote for Obama no matter what. "My job is not to worry about those people. I'll never convince them they should take personal responsibility and care for their lives," he said.
After appearing to write off almost half the electorate, Romney later sought absolution, admitting that his comments had been "completely wrong", but the damage was done.
Head to head
Obama had the momentum coming out of the Democratic convention, but Romney, whose campaign had promised "zingers" galore, stole it back at the first presidential debate on October 3 in Denver, Colorado. Romney's clear, calm and commanding performance – combined with Obama's bizarre no-show – catapulted the Republican into the lead in national polls.
There was palpable relief from Obama supporters when he came out firing on all cylinders for the second presidential debate on October 16. Romney's assured overall performance was overshadowed by his response to a question about equal pay when he used the ill-conceived phrase "binders full of women" to refer to the resumes he was given while governor of Massachusetts.
In the debates, Romney also revealed his plan to cut the budget deficit by pulling funding from public broadcasters such as PBS, who broadcast iconic children's show Sesame Street. This idea led to a show of public support for Big Bird, and #occupysesamestreet was soon trending on Twitter.
Eastwood's invisible friend
It's not often you get to watch a Hollywood legend arguing with an invisible president, but that's just what happened when Clint Eastwood, endorsing Romney at the Republican National Convention, decided to show off his acting skills. Who better to play Obama in the rambling duologue than an empty chair?
The chair, of course, was later given the right to reply.
The October Surprise
US presidential campaign watchers often talk of the October surprise: the unexpected event that can upend a race. This year it came in the form of the largest Atlantic storm on record, Hurricane Sandy, which came crashing into the United States on October 29. Campaigning was put on hold as the superstorm laid waste to entire communities in New Jersey and New York, claiming more than 110 US lives, shutting down the stock exchange and leaving millions without power.
The storm provided Obama the opportunity to display his leadership skills in a time of crisis. The Romney campaign, on the other hand, had no choice but to put its fiercest attacks on hold and show solidarity. Opinion polls in the aftermath of the disaster showed Obama blunting Romney's momentum if not regaining some of his own and the president retained that slim advantage going into election day.
Obama's big day
Nerves were abundant on election day. Obama himself admitted to "butterflies," while Romney campaigned right to the last moment in key states Ohio and Pennsylvania. As results trickled in, it soon became clear that the Republican challenger was not hitting the margins he needed and that the coalition of minorities, young people and women that powered Obama's historic 2008 election was intact.
At 11.18pm Eastern time, the nation's first black president was declared the winner – only the second Democrat to win a second term since World War II. The other, fittingly, was his key champion, Bill Clinton. It didn't long for more than half a million people to share this image and subdued victory statement, which the Obama camp posted on Twitter as soon as victory was assured. It has become the most retweeted tweet in the history of the microblogging platform.
Four more years. twitter.com/BarackObama/st…
— Barack Obama (@BarackObama) November 7, 2012