We've read a lot of post election analysis suggesting it was superstorm Sandy, or Hispanics, or Obama's superior ground game that led to Romney's defeat.

There have even been several articles hinting that Romney himself is to blame, largely because he listened to consultants, or his GOTV operation was screwed up, or he wasn't conservative enough.

But I think this piece by Michael Hirsh in National Journal distills the essence of Romney's problem:

But in the end, Obama secured a second historic election victory-in the face of staggering unemployment-largely because the alternative portrait that Romney presented to the country was far too incomplete. By failing to fill in critical details that would have fleshed out both his personality and his policies, the Republican challenger gave the American people a mere pencil sketch of a candidate. It wasn't enough, and it was much too abstract. Too many voters couldn't figure out which Romney would show up in the Oval Office. Would it be the Massachusetts-moderate redux they saw in the last six weeks of the campaign, or the right-wing ideologue from the Republican primaries who embraced a small-government zealot, Rep. Paul Ryan, as his running mate?

That's not to underrate the savvy, and very savage, campaign that the Obama team ran, one that ruthlessly exploited all of these Romney weaknesses and cost the GOP candidate critical blocs of female and Hispanic voters who didn't buy the reality of Moderate Mitt. For all of the fretting about how $5 billion in campaign spending left the nation with something close to the status quo ante-a Democratic president and Senate, a GOP House-perhaps the most successful chunk of advertising money ever spent in modern American political history was the initial $50 million or so the Obama team devoted last spring to defining Romney as an exploitative, job-exporting Wall Street plutocrat.

In a dynamic that played out much like 2004, when Democratic challenger John Kerry failed to respond to the Republicans' "Swift Boat" attacks, Romney never responded effectively to the fat-cat charges. And he never overcame that image, as a blanket of Obama ads kept up the attack through Nov. 6 in the battleground states. "I think they were very smart in defining him early. The early ads paid off," says GOP strategist Rick Tyler, who helped Newt Gingrich defeat Romney in the South Carolina primary by portraying him similarly. "I don't think he ever really recovered."

The Obama attack successfully neutralized Romney's main argument that as a businessman and numbers whiz, he was best suited to fix the economy. Postelection polling suggests that even though Romney had slightly higher numbers on economic performance than Obama in some polls, his advantage there was eclipsed by doubts about the soundness of his policies and his evenhandedness. According to pollster John Zogby, while most voters on Tuesday cited the economy as their top issue, as expected, 52 percent said that Romney's policies would favor the wealthy, while a plurality of 43 percent said that Obama's policies more greatly benefit the middle class.

Part of Romney's problem was that the primaries drained his war chest and he couldn't spend any money he raised for the general election until after the convention.

But Hirsh is right; Romney let the Obama campaign define him and he never effectively countered their image of him as a rapacious, evil capitalist even after he was able to advertise in response to those charges. The flip flopping certainly didn't help and while the voter gave Romney high marks in his ability to better handle the economy and deficit than Obama, the issue of trust dogged him throughout the campaign.

It might be seen in retrospect that the video that emerged of Romney talking about the "47%" did more damage than was realized at the time. It played directly into the tens of millions of dollars in advertising by the Obama campaign that defined Romney as a heartless businessman.

In the end, Romney couldn't overcome his own shortcomings.