In the annals of the Most Disastrous Shows Ever, there is a new entry. Folk-rock singer Michelle Shocked had the plug pulled on her concert Sunday night after launching into an anti-gay-marriage speech that led most of the audience to walk out.

Did we mention that her fans largely lean well to the left, thanks to the liberal politics that previously infused much of her music, and that the gig where she chose to come out (so to speak) as an Old Testament-citing preacher on homosexual issues was in the heart of San Francisco?

Word of the debacle began spreading via social media even before the operator of Yoshi's interrupted Shocked's performance to announce that, as a gay man, he could not allow the show to continue and she would have to leave the stage. Ironically, Shocked had spent much of the show asking the crowd to engage with her and even pick her set list via Twitter. It's unclear whether she had any idea that, within hours, outraged former fans would be using that same forum to declare that they believe her career is over.

From all accounts, the first set had gone great, but when Shocked returned for the second set, she began talking about the evils that will result if California's Proposition 8 is overturned by the courts, to allow gay marriage in the state. Shocked cited verses from the Old Testament condemning homosexuality, first in English and then, puzzlingly, in Spanish. She even told the crowd that they "could go on Twitter and say 'Michelle Shocked says God hates f--s'," although that particular line was interpreted differently by some on hand, as either ironic or completely sincere.

The tweets that came from her account during the Yoshi's show were actually made by a patron named Matt Penfield, who'd been invited up during the uneventful first set to act as Shocked's Twitter intermediary. When things started to go very badly in the second set, Penfield not only left the stage but exited the auditorium to mill in the lobby with other confused and outraged fans who were trying to make sense of what had just happened.

"It was a very painful experience to go through," Penfield told Yahoo! Music. He not only sat on stage with Shocked for most of the show but visited with her backstage during the break. "To be that close to someone who is clearly having a breakdown of some sort is not an emotionally comfortable place to be. I'm still a little bit shaken up. And I don't like to see people vilified"—as he's well aware Shocked is being today. "I still love her music and I'm not going to delete her from my playlist or go smash CDs. But if she has made a conscious decision that she is going to use the stage to espouse beliefs that are hateful and damage groups of people, she probably should not be charging money for a concert. If she wants to sit on a panel at a conference or go to a religious festival, I think in that context she should say whatever she wants. But I do think that doing it as a bait-and-switch at a concert performance is really unfair and not showing respect to people."

Penfield said he was shocked—yes—when Shocked began talking about homosexuality, but that in retrospect, he thinks that her doing this specifically in San Francisco was planned and not spontaneous. Perhaps the always brash singer/songwriter believed she was speaking truth to power by boldly coming out against homosexuality in the heart of the gay community?

Mind you, this is a performer who once started a video by spray-painting an anarchy symbol on a sidewalk... whose most famous album cover shows her being held by police in a chokehold... who has spoken out against George W. Bush and other Republicans as forcefully as Steve Earle or any other avowedly liberal singer... and who was recently arrested at an Occupy protest.

At the beginning of the show, "Michelle came on stage and seemed visibly anxious and nervous, and took the mike and said that she was really scared and afraid, and that she didn’t really know how the show was going to go— which seemed a little unusual," recalled Penfield. "At one point in the first set she even said, 'You all seem very nice, but I’ve been in rooms of nice people before and sometimes they turn on you.' That was a throwaway line, but one that seemed siginifcant later. After the first set I went backstage with her to the green room and she said that she had been terrified coming up from L.A. because it was going to be a big deal for her to play this show. You can deconstruct from what happened later what she was referring to. In retrospect, it seems clear that this whole thing was premeditated—if not the exact language she used, then that this was where the show was eventually going to go."

The first set went great, from all accounts, even though Penfield thought it was odd when, at the start of the show, Shocked said she needed an on-stage tweeting volunteer and added, "Does anybody feel the invisible person in the room?" Said Penfield, "My family is fron the South and all Baptists, so for me, that’s kind of the code that people use when they’re talking about Jesus or God. I didn't know what her faith-based situation is, but clearly she was looking for someone to identify" as a fellow believer. Despite some raised hands, no one was willing to go on stage, so Pinfield finally volunteered, because after "5-10 minutes" of this, he was afraid the show wouldn't go on otherwise.

At first audience members were confused when she explained that she wanted them to vote on the order of the sets that had been posted outside the door—one labeled "truth" and one "reality." Eventually it came to a Twitter vote and the audience voted for "truth" first, which involved playing her classic Short Sharp Shocked album in its entirety. But after an intermission, Shocked hadn't even gotten to any music when she started talking first about the importance of social media to carry on a dialogue with her fans off-stage, and then about Proposition 8.

"She started reading some tweets from the stream and having a dialogue about people's impressions, talking about how she was feeling brave at this point and that she was doing the right thing. Then the tone of the conversation became extremely religious and she began talking about the two things most important to her being Jesus Christ and freedom. Then she talked about how she had just come from a prayer meeting the night before, and the people in her prayer meeting were really worried because these are the end times, and they’re the end times because Prop. 8 is going to lead to ministers marrying gay people with a rifle to the head. At which people got a little riled up; then there started to be some call and response from the crowd about what she meant. She started exhorting the crowd very specifically to go ahead and tweet or write and say that Michelle Shocked says God hates f--s, and some other references to the Bible denouncing homosexuality as sinful and abhorrent.

"At that point a lot of people started getting up and walking out. We didn’t understand if this was for the sake of art or an actual rant. Then she delivered the same Bible verses in Spanish. At that point personally I felt like I was an emotional hostage, and the night of entertainment had become a night for her to deliver this intense personal polemic that, in hindsight, it felt like she had been carrying around since she got on stage, while we were strapped in waiting for her to deliver it."

At least one fan on Twitter believed that the "God hates f--s" line was spoken ironically, as if she were predicting that that's what her message would be reduced to. But Christine Penfield, the on-stage tweeter's wife, is one of those saying there was only one way to take what she was saying. "She said 'Please tweet that Michelle Shocked said on stage that God hates faggots.' There was no irony," says Christine, who used the hashtag "#takingmyhusbandback" as the show fell apart. "I don't really know what's going on with Michelle Shocked, but I really hope it's a mental breakdown of sorts."

Adds her husband, Matt, "I will say from a personal perspective that I’ve been around musicians my whole life and done a lot of tour work for people, and also been around people who have pretty serious emotional problems. When people ask if she seemed high or drunk, she didn’t. She seemed like someone who had actually gone off medication—anxious and rocking back and forth and a lot of activity and about to explode with emotional anxiety. I have a lot of compassion for her, because she’s clearly processing some heavy emotional s---, but she shouldn't be doing it in front of a room full of strangers."

Shocked's career as a concert performer is clearly in some jeopardy, since much of her audience consists of gay people or sympathizers—and she was even identified as lesbian herself for much of her career (falsely, she's repeatedly said). Daily Kos wrote: "I think it is safe to assume that she has effectively soiled herself to the point of only attracting folks from Westboro Baptist Church, NOM and the Family Research Council to future concerts."

Shocked has admitted in the past that she was having a hard time reconciling her live-and-let-live attitudes with what her pastor was preaching. For anyone wondering how Shocked could reconcile a generally leftist view of politics with an understanding of sexual mores that skews to the right, it's worth noting that her conversion took place in the '90s at the West Angeles Church of God in Christ, one of the largest African-American congregations in California, where she would have been among the few white congregants. It's far more common among black evangelicals than among white churches for parishioners to steer well to the left on most political issues but still adhere to highly conservative views of sexuality.

In a 2008 interview with Edge, a Dallas gay publication, she said, "I’m here to say not that homosexuality is wrong. I’m here to say that there is reconciliation through the blood of Jesus Christ for every human being on the face of this earth. And no one is entitled to speak on God’s behalf and say who does and who doesn’t have that right. Because that price was paid—purchased by the blood of Jesus Christ... Homosexuality is no more or less a sin than fornication. And I’m a fornicator with a capital F.”

Right now, that F stands for Fail, in a major way—unless Shocked meant for her speech to be so offensive that it not only alienated the evening's patrons but the vast majority of her fan base. Will she apologize, or is she just contrary enough (and convicted enough, as an evangelical) to stick to her guns? So far, that Twitter account she promised to use to keep in touch with her fans has been strangely silent.