It's an open secret that American journalists lean to the left. For 40 years, surveys have found that self-described liberals in the media outnumber conservatives by as much as five to one.

President Obama's rise to power has supercharged journalists' liberal inclinations. Going into the 2008 election, Slate -- an online, Washington Post-owned news magazine -- was the only media organization that actually polled its staff, to my knowledge. Obama won by a landslide: 96 percent. At the Post itself, omsbudsman Deborah Howell acknowledged after the election that she had voted for Obama, along with "most Post journalists." In August 2008, she reported that the Post had given Obama front-page coverage three times more often than McCain -- a "disparity ... so wide," she admitted, "that it doesn't look good."

During the 2008 campaign, the American people sensed that the media were in Obama's corner. In July 2008, a Rasmussen survey found that more than three times as many likely voters "believe most reporters will try to help Obama with their coverage" rather than McCain. A Fox News/Opinion Dynamics poll found that almost 70 percent of Americans believed "most members of the media" wanted Obama to win.

Now we have new revelations of media bias -- perhaps the most dramatic yet -- with the release of e-mails from Journolist, an invitation-only listserv founded in 2007 by Washington Post staffer Ezra Klein. Journolist members included about 400 journalists, editors, bloggers, magazine writers, academics and policy wonks -- among them dozens of straight-news reporters from organizations such as Time, Newsweek, the Washington Post, the New York Times, the Associated Press, Reuters, the Economist, Politico, PBS and a large NPR affiliate.

Recently, a website called the Daily Caller obtained Journolist's e-mail archives. The e-mails resoundingly confirm the public's image of liberal journalists as cheerleaders for the Democratic Party, and especially for Obama. At Journolist, news reporters collaborated with open partisans to craft talking points to champion Obama and his agenda.

In September 2008, for example, when McCain named Sarah Palin as his running mate, Journolist participants strategized about how to poison Palin's candidacy.

Daniel Levy of the Century Foundation wrote that Obama's "non-official campaign" would need to mount a coordinated attack. "This seems to me like an occasion when the non-official campaign has a big role to play in defining Palin, shaping the terms of the conversation and saying things that the official [Obama] campaign shouldn't say -- very hard-hitting stuff ... scare people about having this ... right-wing Christian wing-nut a heartbeat away." He exhorted fellow J-listers to "bang away at McCain's age."

Time's Joe Klein linked to his own article on Palin -- partly drawn, he said, from Journolist brainstorming. "Here's my attempt to incorporate the accumulated wisdom of this august list-serve community," he wrote, calling Palin's ideology "militant."

In April 2008, when ABC News raised the issue of Obama's 20-year relationship with antiwhite radical Rev. Jeremiah Wright, many J-listers immediately sensed a threat to an Obama victory. They urged their compatriots to bury the story and to attack any journalist who might consider covering it.

"What is necessary is to raise the cost on the right of going after the left," exhorted Spencer Ackerman of the Washington Independent. He advocated racial smears: "Take one of them -- Fred Barnes, Karl Rove, who cares -- and call them racists. ... This makes them 'sputter' with rage, which in turn leads to overreaction and self-destruction."

Many J-listers routinely flaunted their political biases. David Weigel -- a blogger who covered conservative politics for the Washington Post -- maligned conservatives as racists and "morons." After Rush Limbaugh was hospitalized, Weigel expressed a wish for his death. An NPR affiliate's news producer chimed in that Limbaugh's death would make her "laugh ... like a maniac."

Is Journolist a smoking gun that reveals a grand liberal media conspiracy? I don't think so. In my years as a journalist, I've concluded that bias is largely the product of the insular, cloistered world in which most media people move. When nearly everyone around you shares your worldview, groupthink is the inevitable result.

Media people, like the rest of us, also covet "insider" status -- they want to be part of the club. Often, that can mean snickering together at conservatives like Michele Bachmann or Sarah Palin while treating a liberal icon like Keith Ellison with kid gloves.

Throw in a strong dose of pride -- "we are the enlightened few" -- and it's no wonder that many journalists view themselves as entitled to lead the rest of us to the promised land of liberalism.

Katherine Kersten is a Twin Cities writer and speaker. Reach her at kakersten@gmail.com.