The surprise pick of Alaska Governor Sarah Palin as the vice presidential running mate of Senator John McCain is indicative of a sharp political crisis within the Republican Party.

With barely a year and a half in office as the governor of the country’s least populous state, Palin had been generally ruled out as a potential nominee. She herself told the Washington Post earlier this year that her selection was an “impossibility.” Much of the media responded with incredulity to the announcement made by McCain in Dayton, Ohio Friday.

Until two years ago, Palin was a part-time mayor of an Anchorage suburb of less than 8,000 people. Before that, the 44-year-old mother of five had served on the local PTA and had gained some recognition as a star high school basketball player and contender in an Alaskan state beauty pageant.

She won an upset victory in the gubernatorial race in 2006, but remains a virtual political unknown outside of her home state, even within the Republican Party.

Asked in a Fox News interview about how well McCain and Palin knew each other, McCain’s campaign spokeswoman Nancy Pfotenhauer replied: “You’re running flat into the wall of my ignorance here ... I truly have no indication whatsoever the extent of a relationship that exists with the governor of Alaska.”

Similarly, the Republican senator from Texas, Kay Bailey Hutchison, told MSNBC News that she did not “know much about her.”

Palin’s outsider status has been touted as a plus from the standpoint of McCain’s attempt to present himself as a “maverick” and “reformer”—an increasingly difficult task given his intimate ties with Washington lobbyists. Palin is herself a political ally of big oil, and has benefited from campaign contributions from an Alaskan oil firm implicated in the state’s roiling political scandals.

More importantly, deep divisions within the Republican Party itself have motivated her selection. Other better-known potential vice presidential candidates, including Mitt Romney and Tom Ridge, face stiff opposition from within the party, especially from its politically potent right-wing Christian evangelical wing, where McCain himself enjoys scant popularity.

Among that constituency, which has provided the Republicans with their only popular electoral base, Palin’s selection was celebrated as a major political victory.

While her name was barely mentioned in the extensive media speculation about McCain’s choice, she was a favorite of the Christian right. In an interview with CBS News on August 8, Southern Baptist political leader Richard Land issued a sharp warning that McCain’s vice presidential pick would be “the most important choice he’s going to make in this entire campaign.” There was “no room for error, no margin for doubt,” he added.

If the Republican nominee chose a running mate who supported abortion rights, Land warned, “it will confirm the unease and the mistrust that some evangelicals—and don’t forget this, social conservative Catholics—feel about McCain.”

Asked whom the Christian right would like to see chosen for the position, Land named Palin. He stressed that her “pro-life” credentials had been burnished by her giving birth in April to a child with Downs Syndrome and her public statements that she would never consider having an abortion. Land also pointed to her lifetime membership in the National Rifle Association as a political asset.

Palin has also won support within these circles by campaigning against same-sex marriage and calling for the teaching of creationism in public schools.

Within her home state of Alaska, the selection of Palin for the number-two spot on the Republican ticket was met with some amazement.

The longtime political columnist for the Fairbanks Daily News-Miner, Dermot Cole, told the Associated Press that McCain’s choice was “reckless” and questioned Palin’s qualifications for the job.

“Sarah Palin’s chief qualification for being elected governor was that she was not Frank Murkowski,” Cole said, referring to her Republican predecessor, who went down to a crushing defeat in his re-election bid thanks to budget cuts and a series of corruption and nepotism scandals. “She was not elected because she was a conservative. She was not elected because of her grasp of issues or because of her track record as the mayor of Wasilla,” Cole added.

Adding to the surprise at Palin’s selection is the fact that the Alaska governor is facing an ethics probe of her own. The state legislature voted last month to hire an independent investigator into the case, which stems from the controversial firing of the state’s public safety commissioner, which has been linked to the official’s refusal to fire a state trooper involved in a bitter divorce with the governor’s sister.

One obvious motive for picking Palin is that she is a woman and therefore her candidacy can be used to promote the McCain campaign’s attempt to win over disaffected Hillary Clinton voters. At the rally in Dayton announcing her selection, Palin made a pitch along these lines, signaling a bid by the Republican Party to compete with the Democrats on the basis of gender politics.

“I can’t begin this great effort without honoring the achievements of Geraldine Ferraro in 1984, and, of course, Senator Hillary Clinton, who showed such determination and grace in her presidential campaign,” Palin told the Republican crowd. “The women of America aren’t finished yet, and we can shatter that glass ceiling once and for all.”

Ferraro, the 1984 Democratic vice presidential nominee, reciprocated by telling Fox News that McCain’s choice was “historic” and affirming that there are “a lot of women who are disaffected by the way Hillary was treated” by the Obama campaign and the media.

Given Palin’s hardline anti-abortion rights views, however, it appears highly unlikely that she will succeed in winning over large numbers of women who voted for Clinton in the Democratic primaries.

Democratic campaign officials gloated over the choice, saying that Palin’s nomination would deflate any attempt by the Republicans to cast Obama as unfit for the presidency because of his relative lack of political experience. “Experience is being taken off the table, considering you’re putting someone within a heartbeat of the presidency with the thinnest foreign policy experience in history,” said Obama campaign spokesman Bill Burton.

The “heartbeat away from the presidency” theme is likely to persist, given that McCain, who celebrated his 72nd birthday on the same day that he announced his vice presidential running mate, would be the oldest person ever inaugurated for a first term in the White House and has significant health problems.

The prospect of Palin, who has no experience and no known views on any foreign policy issues—or, for that matter, on most domestic ones—taking the helm as president may give pause to significant layers within the ruling establishment itself.