In general, when a politician leaves a party, you ask "why?" With Specter, the more rewarding question is "who?" In this case, there's an answer: Pat Toomey and the Club for Growth. Toomey is the conservative ex-congressmen mounting a primary challenge against Specter. The Club for Growth is the monomaniacally anti-tax organization that's funding it. And Specter's defection is the direct result of that effort. He said as much at his press conference. That is to say that Specter's defection is the direct result of the Republican tendency to challenge unreliable politicians. It's a strategy that Democrats have, at times, envied: As the argument goes, Republicans have more party unity because they have less tolerance for betrayal. And that's probably true. There were a lot more Democrats who voted for Bush's tax cuts than there were Republicans who voted for Obama's stimulus bill. But in recent years, no Senate Democrats have switched parties, while at least two Republicans have done so...

The Financial Times has a good story today on a new twist in the mortgage market. Namely, banks have stopped offering mortgages in buildings that haven't already sold a sufficient quantity of units. In one case, a buyer with "stellar credit" and a 25 percent downpayment couldn't get a mortgage because the luxury development she wanted had only sold three of 46 units. This is not, on the bank's part, a crazy argument: Developments that don't sell sufficient units have massive problems. The water stops working because the pipes freeze. The heating bill is unpayably high. The units fall into disrepair. The developer defaults and can no longer pay maintenance costs. Eventually, the residents who have bought homes walk away from their mortgages. For a pretty good look at this dark cycle, check out this "This American Life" episode . But it becomes a chicken-and-egg problem. If you can't get mortgage financing to sell the first homes in a development, you can't sell the rest of the homes in...

The Washington Post confirms : Pennsylvania Sen. Arlen Specter will switch his party affiliation from Republican to Democrat, according to sources informed on the decision. Specter's decision would give Democrats a 60-seat, filibuster-proof majority in the Senate assuming Democrat Al Franken is eventually sworn in as the next Senator from Minnesota. (Former Sen. Norm Coleman is appealing Franken's victory in the state Supreme Court.) Specter as a Democrat would also fundamentally alter the 2010 calculus in Pennsylvania as he was expected to face a difficult primary challenge next year from former Rep. Pat Toomey. The only announced Democrat in the race is former National Constitution Center head Joe Torsella although several other candidates are looking at the race. The number 60 doesn't assure 60 votes on any particular priority, but it's a tremendous psychological advantage. It means that there are 60 votes with a baseline incentive to see a successful Democratic Party rather than...

Swine flu is obviously a bad thing. But it's a bad thing with outrageously bad timing. Mexico, in particular, was in economic trouble before. The situation is dire now. The sort of policies you implement to quarantine a disease are the reverse of the sort of policies you implement to grow an economy. One requires an acceleration of transactions. The other requires a cessation of them. According to The Financial Times , Mexico is thinking of "shutting down" the country's capital. The immediate next step, according to the mayor, will be to close the transportation network. Restaurants that can hold more than 50 people have been barred from opening for business. Factory shifts are going to stagger and slow so fewer people are crowded into one place at one time. You can imagine what's happened to tourism. The recession had already slowed Mexico's economy. Now swine flu is going to bring it to a stop. And if Mexico goes down, that of course has major ripple effects on other countries and...

This is all getting a little silly. From Dave Weigel's article on the efforts of pro-life Kansans to derail Kathleen Sebelius's nomination: According to [David Gittrich, the long-serving state development director of Kansans for Life.], when Brownback turns his sights on the governor’s race he’ll gave to “reestablish his credentials as a pro-lifer” and explain his vote. “All the pro-life votes in the world don’t make up for supporting Kathleen Sebelius,” said Gittrich. “This is like saying, ‘I’m against the Holocaust and Nazi Germany but I’d like Hitler to be in charge of the health care center.’” Charming. And this Washington Times editorial arguing against appointing Rosa Brooks as an adviser to the Undersecretary of Defense takes much the same tack: President Obama is surrendering national security with a radical appointment at the Defense Department. Rosa Brooks, this month made adviser to Undersecretary of Defense for Policy Michelle Flournoy, will be in a position to do...

• The First 100 Days...Of the McCain Administration? • Was Tim Geithner a radical nationalizer? • Shortage of doctors proves obstacle to Obama's goal. • Republican spending cuts: An eerily prescient indicator of natural disaster? • Reid to McConnell: "This is a seat for you at the table; we hope you take it."