Boston, Mass. (CBS) -- Mitt Romney's campaign got its first hint something was wrong on the afternoon of Election Day, when state campaign workers on the ground began reporting huge turnout in areas favorable to President Obama: northeastern Ohio, northern Virginia, central Florida and Miami-Dade.
Then came the early exit polls that also were favorable to the president.
But it wasn't until the polls closed that concern turned into alarm. They expected North Carolina to be called early. It wasn't. They expected Pennsylvania to be up in the air all night; it went early for the President.
After Ohio went for Mr. Obama, it was over, but senior advisers say no one could process it.
"We went into the evening confident we had a good path to victory," said one senior adviser. "I don't think there was one person who saw this coming."
They just couldn't believe they had been so wrong. And maybe they weren't: There was Karl Rove on Fox saying Ohio wasn't settled, so campaign aides decided to wait. They didn't want to have to withdraw their concession, like Al Gore did in 2000, and they thought maybe the suburbs of Columbus and Cincinnati, which hadn't been reported, could make a difference.
But then came Colorado for the president and Florida also was looking tougher than anyone had imagined.
"We just felt, 'where's our path?'" said a senior adviser. "There wasn't one."
Romney then said what they knew: it was over.
His personal assistant, Garrett Jackson, called his counterpart on Mr. Obama's staff, Marvin Nicholson. "Is your boss available?" Jackson asked.
Romney was stoic as he talked the president, an aide said, but his wife Ann cried. Running mate Paul Ryan seemed genuinely shocked, the adviser said. Ryan's wife Janna also was shaken and cried softly.
"There's nothing worse than when you think you're going to win, and you don't," said another adviser. "It was like a sucker punch."
Their emotion was visible on their faces when they walked on stage after Romney finished his remarks, which Romney had hastily composed, knowing he had to say something.
Both wives looked stricken, and Ryan himself seemed grim. They all were thrust on that stage without understanding what had just happened.
"He was shellshocked," one adviser said of Romney.
Romney and his campaign had gone into the evening confident they had a good path to victory, for emotional and intellectual reasons. The huge and enthusiastic crowds in swing state after swing state in recent weeks - not only for Romney but also for Paul Ryan - bolstered what they believed intellectually: that Obama would not get the kind of turnout he had in 2008.
They thought intensity and enthusiasm were on their side this time - poll after poll showed Republicans were more motivated to vote than Democrats - and that would translate into votes for Romney.
As a result, they believed the public/media polls were skewed - they thought those polls oversampled Democrats and didn't reflect Republican enthusiasm. They based their own internal polls on turnout levels more favorable to Romney. That was a grave miscalculation, as they would see on election night.
Those assumptions drove their campaign strategy: their internal polling showed them leading in key states, so they decided to make a play for a broad victory: go to places like Pennsylvania while also playing it safe in the last two weeks.
Those assessments were wrong.
They made three key miscalculations, in part because this race bucked historical trends:
1. They misread turnout. They expected it to be between 2004 and 2008 levels, with a plus-2 or plus-3 Democratic electorate, instead of plus-7 as it was in 2008. Their assumptions were wrong on both sides: The president's base turned out and Romney's did not. More African-Americans voted in Ohio, Virginia, North Carolina and Florida than in 2008. And fewer Republicans did: Romney got just over 2 million fewer votes than John McCain.
2. Independents. State polls showed Romney winning big among independents. Historically, any candidate polling that well among independents wins. But as it turned out, many of those independents were former Republicans who now self-identify as independents. The state polls weren't oversampling Democrats and undersampling Republicans - there just weren't as many Republicans this time because they were calling themselves independents.
3. Undecided voters. The perception is they always break for the challenger, since people know the incumbent and would have decided already if they were backing him. Romney was counting on that trend to continue. Instead, exit polls show Mr. Obama won among people who made up their minds on Election Day and in the few days before the election. So maybe Romney, after running for six years, was in the same position as the incumbent.
The campaign before the election had expressed confidence in its calculations, and insisted the Obama campaign, with its own confidence and a completely different analysis, was wrong. In the end, it the other way around.
"They were right," a Romney campaign senior adviser said of the Obama campaign's assessments. "And if they were right, we lose."
Written By: Jan Crawford, CBS News