Since the summer of 2011, Republicans jockeyed to be the party's standard-bearer and challenge Obama on Nov. 6. One by one -- from former Minnesota Gov. Tim Pawlenty to Texas Gov. Rick Perry to Georgia businessman Herman Cain to soon-to-be-former Rep. Ron Paul of Texas -- presidential wannabes dropped out, leaving Mitt Romney, the former Massachusetts governor and son of one-time presidential candidate George Romney alone to wage a campaign to claim the White House.
Romney, in his second bid to be the GOP presidential nominee, was always the front-runner, even though the Republican base wasn't enamored of him, and his lead was challenged from time to time by other presidential hopefuls.
Without a primary challenger, Obama and the Democratic Party worked to define Romney as someone out of touch with the middle class who lacked the chops to lead the country.
After weeks of speculation, Romney tapped Rep. Paul Ryan of Wisconsin, the savvy, likable conservative who masterminded the House Republicans' budget proposal. The impact was immediate -- Ryan revved up crowds and enthusiasm whenever and wherever he spoke.
Obama had begun to pull beyond the margin-of-error range in his lead over Romney when the first debate took place. General consensus: Obama performed badly, allowing Romney back in the race.
Obama performed better -- and won -- the two remaining debates, but he never truly recovered in the polls for weeks.
Romney's campaign was littered with faux pas, including a covertly recorded meeting he had with key fundraisers in which Romney said 47 percent of Americans refused to accept responsibility for their actions and considered themselves victims.
Near the end of the campaign Romney uttered a doozie: Obama sold Chrysler to Italians who, in turn, would build Jeeps in China. He made the remark in auto industry-reliant Ohio and refused to back away from it even though the automaker said it had no intention of moving its U.S. Jeep production to China.
Obama wasn't free of miscues. His shout to a cry of "Boo" during a rally that voting is "the best revenge" drew criticism from Republicans who charged voting was an act of patriotism, not an act of revenge, and commentary by conservative bloggers about what happens when Obama goes off-speech.
The October surprise this year came in the form of Hurricane Sandy, which rushed up the East Coast and made landfall in New Jersey, bringing death, destruction and flooding. As Sandy turned inland, it became a megastorm, inundating several states under feet of snow.
Finally, after months of advertising, robo-calling and visits to swing states by the candidates and their surrogates, voters had their say Nov. 6. Throughout the evening, battleground states -- Pennsylvania, Wisconsin and Michigan, included -- were called for Obama.
When the dust settled, the incumbent claimed victory, 51 percent to 47.3 percent, and collecting 332 electoral votes (270 are needed to win).
Romney, so confident of a win, reportedly didn't prepare a concession speech. But when reports that Ohio was projected to be in Obama's column, the Republican conceded.
"We went into the evening confident we had a good path to victory. I don't think there was one person who saw this coming," an unnamed senior adviser told CBS News.
Florida, with its seemingly eternal voting problems, once again was in the spotlight with reports of an unwieldy ballot and people waiting hours in line to vote. But unlike the 2000 presidential election between George W. Bush and Al Gore, Florida's days-late declaration didn't matter. (It voted for Obama.)
In all, Obama only lost two red states -- Indiana and North Carolina -- that he won in 2008.
The presidential campaign was in the stratosphere as far as fundraising went, with each candidate raising more than $1 billion, federal records showed.
After his short concession speech in Boston, Romney dropped out of the public eye, save for a private lunch with Obama at the White House a few weeks after the campaign ended.
The loss prompted a lot of finger-pointing and soul-searching within the GOP ranks.
"I always hate this kind of scapegoating after the election. When you lose, you lost. Someone asked me, 'Why did Mitt Romney lose?' I said because he got less votes than Barack Obama. That's why," Republican Gov. Chris Christie of New Jersey said.
In December, Republican National Committee Chairman Reince Priebus announced formation of a post-election Growth and Opportunity project, an initiative "to grow the Republican Party and improve future Republican campaigns." Its objective is to review past practices and make "critical recommendations" for the future.
The election outcome also led to online petitions in 17 states asking to secede from the union. Using the Obama administration's We the People website allowing Internet petitions to be lodged with the White House, people in 17 states have asked for permission to leave the union, most citing the Declaration of Independence -- which isn't a legal document -- as their reason.
Third-party candidates lacked the juice they had in 2000 and 2004, but nearly 1.2 million votes were won by Libertarian Party nominee Gary Johnson, a former two-term Republican New Mexico governor.
Green Party nominee and former Massachusetts gubernatorial candidate Jill Stein tallied the second-highest vote count of the minor-party presidential nominees.
In his victory speech, Obama said he would return to the White House "more determined and more inspired than ever about the work there is to do and the future that lies ahead."
"This country has more wealth than any nation, but that's not what makes us rich. We have the most powerful military in history, but that's not what makes us strong. Our university, our culture are all the envy of the world, but that's not what keeps the world coming to our shores," he told the crowd.
"What makes America exceptional," he said "are the bonds that hold together the most diverse nation on Earth."