When we heard earlier today that a gay prostitute claims to have had a three-year-long sexual relationship with the Rev. Ted Haggard, our first reaction was probably the same as yours: "Who's Ted Haggard?"

We asked for an explanation from Salon's Lauren Sandler, the author of "Righteous: Dispatches From the Evangelical Youth Movement." Here's what she tells us:

"Ted Haggard may not just be the most important evangelical you've never heard of, but the most important evangelical, period.

"Joel Osteen may have the largest church in the nation. His Lakewood congregation packs the 60,000-seat Astrodome to bask in his blinding smile and equally blinding promise of the great financial wealth that only faith in Jesus can deliver. But his minions are a paltry bunch compared with the 30 million members of Haggards National Association of Evangelicals.

"Rick Warren may be the bestselling evangelical scribe since the Bible's original autographs. His 'Purpose-Driven Life' has sold more copies than any other nonfiction book in history, that is, if you dont consider the Bible nonfiction. But hes hardly got the ear of the president, with whom he doesn't always see eye to eye (or tooth for tooth).

"And even James Dobson, long heralded as the most influential evangelical in the world, lacks the pull with the evangelical movement he once did. Dobson never takes off his suit jacket, even at his desk, while Haggard can't stand the feel of anything but denim against his skin. Dobson has been seen by many evangelicals as stepping too far into the 'corrupt' dark side of Washington since he launched his PAC, while Haggard manages his influence carefully without the tarnish of politics ever marring his flawless gleam. It's Haggard who is the bionic hero of the young cadets and airmen he ministers to in his own megachurch, just down the road from Dobson's Focus on the Family. In Colorado Springs -- known alternately as the Vatican and the Washington of the evangelical world -- it is Haggard who is king, the crony and the conscience of his youthful parishioners as well as his president.

"Which is why it matters so that Haggard seems to have fallen. The Mark Foley scandal inspired plenty of people to question their devotion to the Republican Party. But Foley is a politician; most evangelicals would already suspect him of thinly cloaking his identity in a three-piece, pinstriped superego. Haggard, on the other hand, has always represented the real deal. He's the one John Wayne would have tapped for his posse. He's the one who represents most how deeply political this evangelical population can be, while always disdaining the notion of politics, always cleaving toward the ranch rather than the Hill.

"If that makes it sound like Haggard and Bush are peas in a pod, well, they are. Haggard participates -- or at least he did -- in weekly White House conference calls, and he and the president like to joke that the only thing they disagree on is what truck to drive.

"Haggard has been preaching against homosexuality with his typical charismatic fire-and-brimstone fervor ever since he founded New Life Church in Colorado Springs. Probably even before then. And if he's right that there is a special place in hell for gay fornicators and drug abusers -- not to mention for liars and charlatans -- I guess he knows where he's headed."

Update: The Denver Post reports that Haggard has resigned as president of the National Association of Evangelicals. In a statement released by New Life Church, Haggard said he could "not continue to minister under the cloud created by accusations made on Denver talk radio this morning."

Correction: As readers have helpfully pointed out, Joel Osteen's Lakewood Church is housed in what used to be called the Compaq Center (formerly the home of the Houston Rockets), not the Astrodome.