Kevin Drum at Mother Jones has a chart showing that in the last five months President Obama was hammered by the mainstream press harder than any of his GOP rivals; there was a 25 point gap between the percentage of his coverage that was positive and the negative stories.These charts and other methods to referee the press are generally lame; assessing press coverage inevitably involved tricky qualitative questions. How prominent was the story? When something terrible happens, like Rick Perry’s debate performances or the Solyndra mess, is it ‘negative coverage’ when the press reports it? Newspapers very friendly to JFK would have had to report on the Bay of Pigs, but they might have told the story less fully than outlets who opposed him, failing to nail down the extent of the President’s personal involvement and responsibility. They would report, but not milk. A negative story can have positive spin.Even so, Drum is right; the media has soured on President Obama in recent months. The liberal press in particular hated his approach to the budget negotiations; many journalists were more interested in writing about possible infringements of American civil rights than in celebrating the competence and judgement involved in the Yemen drone strikes. The Carterization meme, that President Obama is out of touch and dithering rather than Olympian and visionary, has taken hold. Words that could not be mentioned in polite company in 2008 like “inexperienced” and “aloof” fill the air. The truth that President Obama is more McGeorge Bundy than Mother Teresa has begun to sink in.The problem is not, as Drum seems to imply, that the mainstream press is full of closet Republicans who can’t wait to turn on Obama the moment they sense weakness. It is more that many in the press are convinced that Blue Liberal ideas and policies could solve all our problems if forcefully advocated and consistently applied. When a Democrat gets into the White House and things aren’t going well, liberals are much more likely to blame the incompetence of the officeholder than the shortcomings of the ideology. If he had tried harder, spoken more forcefully, negotiated less fecklessly, everything would be fine.What you will not hear often in the torrent of liberal criticism now enveloping the White House, is that regardless of their intrinsic merit in a country in which self described liberals are a tiny minority (less than a fifth), liberal ideas don’t work very well as a governing platform. A Congress seen as too liberal won’t get re-elected; a President seen as too liberal loses political authority and is steadily pushed to the right.The mainstream media tone on Obama has lightened up since he decided to rebrand himself as a mild populist and ‘get tough’ with the GOP. (Cynics seeing Obama do tough are reminded of Tom Lehrer’s “Fight Fiercely, Harvard” pep song, but that’s an issue for another day.) If the poll numbers go up, we will hear much about the revived Obama presidency. If they go down, the press will blame Obama for flawed execution, not the idea that populism could save his presidency.Press bias is real in this country; Kevin Drum would not call it a left or even a liberal bias since from his point of view it is centrist and even a bit corporatist. Fair enough. It is also not monolithic. The New York Times, the Washington Post, the Wall Street Journal, USA Today, the three major networks and PBS/NPR are perceptibly different. And any reporter, any paper, will gleefully toss ideology under the bus to secure a big enough scoop.Efforts to measure bias are tricky, and none of them ever impressed me. But if you want to predict how the tone of President Obama’s coverage will change, watch his success or lack of it at translating standard liberal ideas into law and policy. The more he succeeds, the more he will be seen as ‘historic’, ‘visionary’ and, magic word of hope and wonder, ‘transformational’. The progress will be hailed, the direction for the most part not questioned.