The Tea Party has evolved from a cable-news curiosity into a political and cultural force that decides elections and casts an Everest-sized shadow over the coming midterms. It has spawned countless articles, essays, and op-eds that attempt to explain it, define it, and gauge its power.

So it is easy to forget that, in the weeks and months after CNBC’s Rick Santelli delivered his February 19, 2009, jeremiad against the Homeowners Affordability and Stability Plan, in which he called for “all the capitalists” to come to Chicago for a “tea party,” none of this seemed inevitable. Santelli spent days backpedaling, telling MSNBC’s Chris Matthews, for instance, that he had “great respect for the administration” and wanted it to “win.” “I’m not coming down hard on Barack,” Santelli insisted.

In fact, as the Drudge Report and other conservative outlets pointed readers to a video of Santelli’s rant, and people around the country began organizing Tea Party rallies against President Obama’s agenda, the broader media world was mostly indifferent. For a brief moment, the Santelli affair was dismissed by many as just another made-for-cable-news drama that would fade when the next one arose.

The left press, in particular, fundamentally misread the Tea Party and inadvertently helped it congeal into a real political force. Its mistake was journalistic: oversimplifying a genuinely complex phenomenon. But the cause was political: a desire to destroy a perceived threat. The new towers of the left media, sites like Talking Points Memo, The Huffington Post, the Center for American Progress’s ThinkProgress, and programs like MSNBC’s The Rachel Maddow Show, did not take the movement seriously and their initial coverage was mocking.

The exception, a piece by Mark Ames and Yasha Levine published on February 27, 2009, on Playboy’s Web site that attempted to situate Santelli and his rant inside a coordinated “rightwing PR machine,” foreshadowed where the left press was headed once mockery failed. CNBC threatened to sue, and Playboy removed the piece from its site.

By the summer of 2009, when activists flooded town halls to oppose cap-and-trade and health-care legislation, and into 2010, when the movement started deciding the winners of some early Republican primaries, the liberal press adopted the strategy of the Playboy piece and began trying to discredit the Tea Party by exposing its most extreme right-wing elements and its ties to big business.

An early signal that this strategy shift was coming was a March 23, 2009, piece by Lee Fang for ThinkProgress in which he alerted liberals to what he considered the bogus conservative scheme:

The “tea party” protests nationwide are being coordinated by the conservative public relations firm Freedom Works, which is run by former Majority Leader Dick Armey (R-TX). The tea parties are also being supported by Newt Gingrich, through his organization American Solutions For Winning the Future. Members of Congress, such as Rep. Jean Schmidt (R-OH), have appeared at previous rallies. In addition, Fox News’ Glenn Beck promotes the protests, and has launched a website publicizing the events.

Ultimately, neither strategy—derision or conspiracy theory—worked. As the nascent Tea Party movement continues to wield political power, the new liberal press’s effort to knock it down looks like a spectacular failure. The movement thrived on the negative attention from the left, which complemented the constant and shameless boosterism it received from right-wing media. The mainstream media, meanwhile, ignored liberal demands that it spend less time personalizing the Tea Party activists and more time investigating their funding.

I was acutely aware of the media’s treatment of the Tea Partiers because I was one of the first reporters for a left-leaning publication to take the movement seriously. In January 2009 I had moved from the libertarian Reason magazine to a liberal start-up called The Washington Independent. Tasked with covering “the re-making of the right,” I shadowed the young activists who organized the first Tea Party in Washington, D.C., on February 27, 2009.

David Weigel is a contributor to CJR.