Since Sarah Palin’s unexpected announcement that she would vacate Alaska’s governorship before the end of the month, there’s been a lot of head-scratching and asking why, exactly—barely two-and-a-half years into her only experience in major elected office—she decided to go.

The FBI has ruled out a federal investigation. All the other juicy rumors haven’t panned out. So far, the best explanation we have is the one the governor and her allies are offering: that ever since she became John McCain’s running mate, state government has been bogged down with entangling and expensive ethics inquiries. Here’s how she put it in last Friday’s lakeside resignation speech:

Political operatives descended on Alaska last August, digging for dirt. The ethics law I championed became their weapon of choice. Over the past nine months I’ve been accused of all sorts of frivolous ethics violations – such as holding a fish in a photograph, wearing a jacket with a logo on it, and answering reporters’ questions.

Every one—all 15 of the ethics complaints have been dismissed. We’ve won! But it hasn’t been cheap—the State has wasted THOUSANDS of hours of YOUR time and shelled out some two million of YOUR dollars to respond to “opposition research”—that’s money NOT going to fund teachers or troopers—or safer roads.

In her bayside, wader-wearing interviews on Monday, Palin unspecifically revised that figure upwards to “millions” of dollars. And the thrust of her comments on both occasions implied that the bulk of this money has been spent on responding to the dismissed (and, as she’s described them, “frivolous”) ethics complaints made under the Executive Branch Ethics Act, to which, in 2007, she signed major revisions into law. (It’s worth noting that one of the “dismissed” ethics complaints was only dismissed after Palin, under a settlement reached with the Alaska Personnel Board, agreed to reimburse the state for half a dozen plane trips her children took on the taxpayers’ dime. Another resulted in an aide being asked to take ethics training.)

But that $2 million figure doesn’t come close to adding up, unless an entirely other category of expenses is included: the state’s costs to fulfill requests under the Alaska Public Records Act.

Sean Parnell, the lieutenant governor who will take over for Palin, gave us a glance at the full math in an appearance on Fox News Sunday, where Chris Wallace asked him to sum up exactly why his boss was leaving the job.

PARNELL: You know, I think what I heard from the governor really had to do with the weight on her, the concern she had for the cost of all the ethics investigations and the like, the way that that weighed on her with respect to her inability to just move forward Alaska’s agenda on behalf of Alaskans in the current context of the environment. So that’s what I saw.

WALLACE: So basically, she was saying that all of the personal attacks, all of the ethics attacks—that that was preventing her from doing her job. That’s why she decided to quit.

PARNELL: Well, and the fact that it cost—it was costing just about $2 million of state taxpayers’ dollars just to fund the staff to deal with the records requests and the like, and that—that was just over the top, and I think she used the word insane in her—in her remarks.

According to Parnell, it wasn’t just that Palin was feeling bogged down under the weight of the ethics complaints, it was also that costs for filling “records requests and the like” had gotten out of hand.

And maybe Palin meant to include Records Act expenses in her public remarks, with her vague references on Friday and Monday to “opposition research.” It’s not hard to see how Palin or her defenders could construe both categories of expenses as intertwined consequences of some $2 million “Get Sarah” project, launched shortly after her ascendancy to the national scene.

Of course, some requests have come from opponents—like the Alaska Democratic Party—looking for dirt. But most have come from state and national media, and local bloggers and citizens. One woman’s dirt-digging is another’s treasure: a key principle of open records is the presumption that requesters have a right to the information, no matter what their intent is in seeking it. And in our oppositional system some of the most valuable political accountability comes from self-interested political opponents.

Today, the Anchorage Daily News has a story that sifts through the $2 million figure, based on a vague spreadsheet from the Palin’s press office that was e-mailed to reporters.

The spreadsheet, provided to CJR by Mark Thiessen, the Associated Press’s Alaska news editor, and available for download here, illustrates the hazards of the simplistic claim that the records requests stem from political persecution.

Clint Hendler is the managing editor of Mother Jones, and a former deputy editor of CJR.