After all the hype, Sarah Palin wasn't so much a rabbit in the headlights as a Caribou Barbie in the spotlight as she finally straightened her fringe, slipped into one of those trademark power-suits and did battle with her comedy alter-ego, Tina Fey.

In one of the more bizarre pieces of political theatre in American history, the Republican vice-presidential candidate visited NBC's studios in New York at the weekend, to appear in the TV sketch show, Saturday Night Live.

Her decision to perform two brief, scripted sketches on the programme was either a game attempt to face down sneering critics in the liberal media – or recognition that she has little left to lose, following a descent from political sensation to national joke.

Either way, Governor Palin's appearance alongside Mark Wahlberg, Alec Baldwin, and Josh Brolin on Saturday's show demonstrated how difficult it has become for the rest of America to recognise where she begins, and Fey's merciless parody ends. Her appearance was limited to two segments at either end of the hour-long show. In the opening sketch, Fey starred in a fictional rendition of what her first unscripted press conference might be like to watch.

"First off, I just want to say how excited I am to be in front of both the liberal elite media as well as the liberal regular media," said Fey. "I am looking forward to your questions."

Moments later, the camera cut away to the real Ms Palin, identically dressed, with Saturday Night Live's executive producer, Lorne Michaels. "You know, Lorne, I just don't think it's a realistic depiction of the way my press conferences would have gone," Ms Palin said.

The left-leaning Alec Baldwin then stumbled on stage, mistook Ms Palin for Fey, and pleaded with Michaels not to let the two women share a platform. "This is the most important election in our nation's history and you want her, our Tina, to ... stand with that horrible woman?" he said.

When Michaels introduced him to the Alaska governor, Baldwin feigned horror and replied: "I see. Forgive me. I feel I must say this: You are way hotter in person."

Shortly afterwards, Ms Palin walked on to the fake news conference set to deliver the programme's stock opening line. "No, I'm not going to take any of your questions," she told a cheering studio audience. "But I do want to take this opportunity to say, 'Live from New York, it's Saturday Night'."

Ms Palin's decision to appear on SNL follows a month in which Fey's impersonation of the Alaskan governor, helped by the pair's close physical resemblance, has become a national sensation, garnering more than seven million viewers for her show.

The growing popularity of Fey's satire has been mirrored by a sharp decline in Ms Palin's popularity among independent voters, with only one in three now deeming her capable of being vice-president.

Saturday's guest spot was intended to lance the boil. Her final appearance came in the closing skit, a mock news sketch in which SNL presenter Amy Poehler, launched into an extended, Eminem-style rap, about Ms Palin's folksy campaign, with lyrics that included "from my porch I can see, Russia and such."

It ended with a large moose dancing on to the set, followed by the sound of gunshots, a joke sending-up Palin's fondness for hunting. Throughout the sketch, Ms Palin rocked back and forth in her anchor seat, pumping her arms in the air, like a teacher at a brightly-lit school disco.

The governor's appearance may at least have demonstrated that she is in possession of a sense of humour, but the effect on her popularity among undecided voters remains to be seen.

Though her performance will no doubt increase her skyrocketing celebrity, a cynic might venture that it has come to something when a person seeking to become vice-president of the most powerful nation on earth celebrates being an object of derision.

It may also be unwise for Ms Palin to have joked about the fact that party handlers deem her too thick to appear in unscripted press conferences.