Among many charges laid out against her critics in recent days, Gov. Sarah Palin went after the media for employing a double standard in speculating about the reasons for her surprise departure. In a statement on her Facebook page, Palin wrote that “though it's honorable for countless others to leave their positions for a higher calling and without finishing a term, of course we know by now, for some reason a different standard applies for the decisions I make."

But is there anyone else who has resigned under similar circumstances? Politicians leave office all the time due to scandal, health reasons, cabinet appointments, or election to higher office. According to historians who talked to The Daily Beast, however, major figures who dropped out in the middle of their term with a Palinesque air of mystery are hard to come by.

Calls to the governor's office for clarification as to which politicians she was referring to in her Facebook note went unreturned, but several historians said that Palin's resignation appeared to be largely without parallel.

“To be honest I can't think of any [examples],” Julian Zelizer, a professor of history and public affairs at Princeton University, told The Daily Beast in an email. “In general, Americans don't like people who quit and they really don't like people who quit for no reason. So the bar is high for a politician to do something like this.”

One elected official who stepped down early that Zelizer and others mentioned as at least a vague point of comparison is former Sen. Bob Dole, who resigned in June 1996 to focus on the presidential campaign. But Dole was explicit about his intentions. Moreover, he was 73 years old and had some 27 years in the Senate to fall back on; Palin is barely halfway through her first term as governor.

After that, the pickings are slim and involve officials far less famous than the ubiquitous Palin. Steve Gillon, a professor of history at the University of Oklahoma, told The Daily Beast that the best comparison he could come up with was his current boss, former Sen. David Boren, who left office in the middle of his term in 1994 to become president of the University of Oklahoma.

“I am sure there are other politicians who, like Palin, simply walked away from the job. But I can't think of any,” Gillon said in an email. “In the past, politicians who were either weary of public battles or greedy for more money could simply 'check out' for the remainder of their term and hold the title but do little work. Today, getting elected requires so much time and effort most people drop out before the election, not after.”

Historian Ken Ackerman, author of Dark Horse: The Surprise Election and Political Murder of President James A. Garfield, said that the closest recent examples he could come up with were former Sen. Trent Lott and former Speaker of the House Dennis Hastert, both of whom resigned shortly after the Democrats took power in 2007.

In Lott's case, it was widely speculated at the time that his sudden resignation, which came less than a year into his new term as senator, was in response to new ethics laws that would have made it more difficult for him to take work as a lobbyist. "While Lott denied it was the reason for his departure, he founded a lobbying firm with former Sen. John Breaux of Louisiana the next year.

In Hastert's case, there was little mystery regarding his departure as he said he had grown frustrated with life in the minority after holding the most powerful position in the House for years. Colleagues told the press at the time that they were not surprised by the move. In Palin's case, even her father-in-law didn't know her resignation was coming until the morning of the announcement.

Palin's closest comparison might be Harold Stassen, who resigned as governor of Minnesota to enlist in the Navy in 1943. But his case could also be a cautionary one for Palin—despite his service he failed to win the 1948 Republican nomination for president, losing out to Thomas Dewey, and instead became a perennial also-ran, competing in nearly every subsequent presidential election for the next 50 years. A slightly more successful, if morally reprehensible, model might be his contemporary, Happy Chandler, who resigned in 1945 to become commissioner of baseball and returned 10 years later to become governor of Kentucky. He couldn't cut it on the national stage, either: George Wallace denied him a spot on his segregationist ticket in 1968.

As for governors, unless Palin believes it's unfair that, say, former Kansas Gov. Kathleen Sebelius does not merit equal scrutiny for leaving office to take a position in Obama’s Cabinet, or that ex-govs Eliot Spitzer and Jim McGreevey had an easier time of things than she has, it's hard to find anyone who merits comparison. Even Arnold Schwarzenegger, who sports a 33 percent approval rating and could leave the California governor’s office for Hollywood at any time, is sticking things out. For now, it appears Palin is sui generis among America's political dropouts.

Benjamin Sarlin is a reporter for The Daily Beast. He previously covered New York City politics for The New York Sun and has worked for talkingpointsmemo.com.