In this opera production, the pitch is political

But that’s what happened, thanks to a curious inspiration on the part of composer Curtis Hughes. His new work, “Say It Ain’t So, Joe,’’ has a character list that reads like a who’s who of the 2008 election season: Joe Biden, Hillary Clinton, Diane Sawyer, Gwen Ifill, and Samuel “Joe the Plumber’’ Wurzelbacher. The piece was written for the inventive local company Guerilla Opera and premieres tomorrow.

“I’ve never done something like this before,’’ says soprano Jennifer Ashe, who sings Palin’s role. “It’s really exciting to be doing something that’s current and live and vibrant and a character that people know.

“When her name pops up,’’ Ashe says, “I think, I better read, see what’s going on with my character.’’

And come to think of it, Palin seemed ripe for operatic treatment all along. The almost primal passions her candidacy aroused, and the personal and political controversies that dogged it, all fit the recipe for music’s most dramatic form. But it wasn’t the brouhaha that inspired Hughes; it was the sonic possibilities.

Like millions of Americans, he was watching the broadcast of the vice presidential debate in St. Louis last October. Apart from questions of who was winning and who sounded presidential, Hughes noticed something else: The verbal jousts sounded oddly musical.

“I was actually struck by how interesting a musical contrast there was between them, independent of what they were saying,’’ he says during a phone interview. “Initially, I thought that Sarah Palin’s voice was very melodious. And then I realized that it’s only selectively melodious - she’s actually fairly confined and narrow in range for long periods of time, and then when she really wants to make a point she suddenly kind of swoops around.’’

So intrigued was Hughes by the musical difference between Palin’s and Biden’s voices that he derived much of the opera’s music directly from their speech patterns at the debate. “I’m re-creating the exact pitches that were spoken,’’ he explains, “and I’m putting them in a musical context that will sound as though they were meant to be musical all along. Because that’s how I heard some of them during the debate itself.’’

Ashe says that Hughes’s painstaking transcriptions helped her get a handle on Palin’s vocal inflections, and in turn find her way into a closely scrutinized character without falling back on caricature. “I’ve just tried to sort of take my sense of [her] straight from the music.’’

The action in the opera begins in the debate and circles back to it repeatedly. In between come scenes derived from public interviews, Palin’s nomination speech, and a campaign rally. “About half the opera scenes are excerpts from the debate and half of them are other scenes both before and after which relate more or less directly to what’s being discussed in the debates,’’ Hughes says.

Interestingly, when Palin appears outside the debate scenario, her role is sung by another soprano - Guerilla Opera general manager Aliana de la Guardia - to capture her dreamier, more idealistic side. As the opera progresses, the scenes become increasingly fantasy-like. The dramatic sense of time loosens, and the debate excerpts start to fragment as words become unintelligible and Biden, Palin, and moderator Gwen Ifill sing trios together.

“I remembered my own experience of the debate, which is that my attention drifted away at times and came back,’’ Hughes says. “So I thought that it might be interesting to have the music do something similar: to kind of start with a realistic and straightforward presentation but eventually, all sorts of not-quite-realistic, surreal things happen.’’

The instrumental music is split between what the composer calls “elements of traditional, even neo-Romantic opera’’ and “a lot of avant-garde influence,’’ the latter dictated in part by Guerilla Opera’s eclectic ensemble of clarinet, saxophone, cello, and percussion. Sometimes the music acts as a sincere accompaniment to the characters’ words, while here and there it wisecracks behind their backs.

“And I’m not above some good old-fashioned word-painting. Especially when Joe the Plumber comes on the scene - I guess my word-painting tends to get a little more crass,’’ Hughes says with a laugh.

He calls the opera “a light tragedy,’’ a sly but telling indicator that “Say It Ain’t So’’ doesn’t fit comfortably into standard dramatic categories. It has elements of both comedy and tragedy, and is neither satire nor agitprop. So just what is the opera about?

One theme that emerges, the composer says, is “the sense of increasing desperation and eventual abandonment that Sarah Palin expresses during the course of the opera. It begins with her complaining about her treatment at the hands of the media, a recurring theme. And there’s a way both musically and dramatically that the last scene of the opera indicates that she really has been abandoned, at least at that point, by her political party.’’

Still, Hughes adds, he tried to make the opera as open-ended as possible and resist leaving his audience with an easy, sound-bite moral. “I think that one’s understanding of the plotline of the opera will depend on one’s political outlook and also on individual notions of what Sarah Palin really represents. One of her arias concludes with her informing the audience, ‘I am your future.’ I’d like to think that the music at this moment could be understood as either ominous or joyful, or perhaps both.’’

At Boston Conservatory, tomorrow through Sept. 26; www.guerillaopera.com.