It was only a matter of time until Romney finally piled up enough delegates to clinch the nomination on May 29 in Texas. For practical purposes, by then the general election campaign had been going on for months.
For all the words spoken, money expended and attention devoted to the Republican primary fight, the most important thing that happened in the presidential race may have been what wasn't happening at that time: Obama did not draw a Democratic opponent.
For decades, incumbents who've faced either no primary challenge or an insignificant one have been re-elected, while those who've had a serious challenge have not.
"Romney had to move right to win his primary's nomination and Obama didn't have to move left to win his," says Dan Schnur, a former Republican adviser who teaches political science at the University of Southern California. "So while Romney was talking about contraception and immigration, Obama was bragging about expanding offshore oil drilling, cutting the corporate tax and using military drones in Afghanistan and Pakistan."
While the Republicans were busy with their infighting, Obama made a decision in February that would be key to staying competitive over the nine-month march to Election Day: He reversed course and gave his blessing to the big-money independent fundraising groups that he had previously assailed as a "threat to democracy" because of the potentially corrupting influence of money on politics. The candidate who once told supporters to "fight their millions of dollars with millions of voices" decided voices were great, but he'd like those millions of dollars, too.
The money rolled in. Before it was over, the two sides and their allies had spent in excess of $2 billion.
With no primary opponent to worry about, Obama got an early start on softening up his opponent for the fall. One TV ad accused Romney of failing to stand up to "the voices of extremism" in his party. In another, a steelworker called Romney a "job destroyer" and compared his former private equity firm to a "vampire" that sucked the life out of companies.
The cumulative effect was reflected in polls showing that voters saw Obama, not Romney, as the candidate who best understood the concerns of the middle class.
From Inauguration Day, Obama knew it would be hard to live up to the high expectations set during the heady days of his 2008 "hope and change" campaign to become the nation's first black president.
A few weeks into his presidency, he took stock of a country in economic crisis and acknowledged: "You know, I've got four years. ... If I don't have this done in three years, then there's going to be a one-term proposition."
By this summer, Obama had both the burden and blessing of a record to run on. The economy was sputtering along but hardly robust. The president's favorability ratings were higher than Romney's. But his job approval numbers hovered below 50 percent. The jobless rate remained above 8 percent, with each monthly unemployment report driving home that statistic anew.
If Obama's glass was half-full, Romney's was half-empty — actually, almost drained. "It's another hammer blow to the struggling middle-class families of America," Romney said when the jobs report came out in August. He spoke from Nevada, where the economic picture was particularly grim.
Obama played up 29 straight months that private employers had added jobs and surrounded himself at the White House with middle-class families making progress. "Those are our neighbors and families finding work," Obama said. "But, let's acknowledge, we've still got too many folks out there who are looking for work." No economic recovery since World War II had been weaker.
So the two candidates headed in, and out, of their nominating conventions wielding the same campaign arguments they'd been making all year, and still running about even in their support from voters. But Obama had the edge on another important yardstick: