Nate Silver has some details on just how spectacularly badly Mitt Romney performed in last night’s primary and caucuses. He’s following Hillary Clinton’s trajectory, with wins in New Hampshire, Florida, and Nevada, and losses everywhere else. (I believe Obama actually netted one more delegate out of Nevada, but he lost on the percentages). The take away from last night is less that Romney lost than the thoroughness with which he lost in both Missouri and Minnesota, failing to win a single county in either state. Even when Obama was losing states badly to Clinton, he was winning in the cities and college towns. Romney is weak across the board.

Romney has now lost in Iowa, Minnesota, and Missouri, and his performance in the Midwest is getting worse, not better. He’s banking on winning Michigan, which is where he grew up and where his father served as a fairly popular governor. But I see no signs in the polling data that should give Romney encouragement. You’d think a man nicknamed ‘Mittens’ would be a lock to win the Mitten State, but he’s polling behind Gingrich in Ohio, and he’ll probably be in third place there when the next survey comes out. I think Santorum will focus all his energy on winning over the largely Catholic Reagan Democrats in the Detroit suburbs and leave Arizona for Gingrich to mine.

The assumption is that Romney can overwhelm his opponents with superior organization and saturation advertising, but that hasn’t worked so far and it might be counterproductive considering that the more people see of Mitt Romney, the less they like him.

Overall, 55 percent of those who are closely following the campaign say they disapprove of what the GOP candidates have been saying. By better than 2 to 1, Americans say the more they learn about Romney, the less they like him. Even among Republicans, as many offer negative as positive assessments of him on this question.

It’s also a lot easier for Romney to attack Newt Gingrich than it is for him to attack Rick Santorum. What’s he going to attack him for? Being too religiously conservative? Being too sanctimonious? Blasting him for receiving earmarks is just a big yawner.

As things stand, I don’t think Mitt Romney will win in Michigan. He has to hope that the media shines a new light on Santorum’s career and some of his more controversial positions and idiosyncrasies, but it’s not easy to exploit Santorum’s weaknesses while simultaneously trying to convince people you’re a conservative. Blasting Romney’s face all over the airwaves doesn’t seem to work, either. But maybe his people can come up with a really effective ad campaign that can pull him through.

I have less of a feel for Arizona. It seems like a better fit for Romney, and I’m not sure Gingrich has enough left in the tank to get any momentum going. I don’t think Santorum will seriously contest there unless the polls come out showing him in the lead. So, lacking any data or real feel for the conservative electorate there, I can’t predict that Romney will lose Arizona. But he better win, because he can’t afford to get shut out again or the nomination might actually slip out of his grip.

Romney is supposed to be the nominee because he has the money, organization, endorsements, and temperament that his opponents lack. But it turns out that people don’t like his face, he can’t organize worth a damn, no one cares about endorsements, and his temperament is off-putting. Meanwhile, his money advantage is blunted by the Citizens United ruling that allows Super PACs to keep his opponents going on a shoestring budget. Romney’s advantages have so far turned out to not be advantages after all. Even the conservative media has failed to unite behind him.

At this point, even if he wins the nomination, which is still the likeliest result, he’ll be several times weaker than Walter Mondale as a general election candidate. He has now entered the danger zone where he faces the real prospect of epic collapse and failure.