ONE year ago Matthew Yglesias, a blogger, left the Atlantic Monthly to join the Center for American Progress, a powerful liberal think-tank created to counter powerful conservative think-tanks such as the Heritage Foundation. Today, worrying that the media has been devoting too much coverage to right-wing outbursts at town halls, Mr Yglesias seemed to criticise his own institution.

[T]o take a bit of a self-critical look at things, this dynamic wasn’t helped by the rise of a left-wing mass media (blogs, Rachel Maddow, etc.) that was more interested in poking fun at the nuttiest voices on the right than in trying to amplify the concerns of pro-reform voters.

One branch of that "mass media" that seems interested in "poking fun" is ThinkProgress, one of the other Center for American Progress blogs, which usually fact-checks and mocks famous and obscure conservatives like Michele Bachmann ("Bachmann: We should 'make a covenant, to slit our wrists, be blood brothers' against health care reform") and Steven Anderson ("Radical Arizona preacher hopes 'God strikes Obama with brain cancer so he can die like Ted Kennedy.'").

This isn't isolated to ThinkProgress. Talking Points Memo, an award-winning liberal news site that played a major role in exposing a scandal in the firing of some of George Bush's US attorneys, is often given over to coverage of the same thing. One top story reports that "Tea Baggers" have accused a Republican senator of "treason". One of the top stories at the Huffington Post consists of several Republican strategists answering a ridiculous question—should Dick Cheney (who has a pacemaker and will be 71 at the next election) run for president?

But the biggest piece of evidence on Mr Yglesias's side is the coverage that liberal blogs and MSNBC gave Sarah Palin's Facebook post—not even a speech—that alleged a health-care reform bill would include "death panels". Greg Sargent, a blogger for a Washington Post offshoot who relentlessly asked Republicans whether they agreed with Mrs Palin, now wonders whether all that coverage forced the White House off stride.

The basic problem for liberals is time. There are only so many hours of news to fill; every minute spent talking about a conservative outrage is a minute not spent talking about, say, whether unions would walk away from the table if the White House didn't include a public option in the health-care bill. The latter story is about Democratic power; the former is about Democratic weakness. How low must the self-confidence of the majority party be if it can't take some ribbing from powerless conservatives?

The second problem is tone. Like it or not, liberalism is the ideology of the big cities. When liberal interest-groups mock conservatives, they often sound like Noel Coward characters making fun of the rubes.

The final problem is, ironically, the market. Wonkish writing about the Democratic agenda does not sell. Mockery does. (That silly Dick Cheney story at the Huffington Post is on its way to 2000 comments from readers.) There's an impetus for members of the new liberal media to be the first with a particularly juicy right-wing attack. And that's ironic, because the internet has provided them with unlimited space to cover whatever they want. There's not really any need to package the most salacious story for the front page. Those stories simply provide a more immediate reward—links, traffic, possibly an obscure Republican backing down—and the effect of crowding out the liberal agenda is too delayed to notice.