First and foremost he was running against President Obama and the President's grassroots supporters, including me.
The following additional reasons pale in comparison:
President Obama had Joe Biden, Michelle Obama and Bill Clinton.
Romney had Paul Ryan and George W. Bush's neocon strategists running his campaign while W was speaking at an investment conference in the Cayman Islands.
A majority of the electorate saw Romney as a "vulture capitalist," as someone who used other people's money to buy and sell other people's businesses – not a job creator.
Women favored Obama by 55 percent and unmarried women preferred him by 68 percent.
70 percent of Hispanics and Asian Americans voted for Obama.
Romney told one too many obvious lies.
And, last but not least, as fundamentalist Christians would say, "God intervened."