The reviews of Sarah Palin's latest television appearance tumbled in yesterday and they were ugly. In only the third major broadcast interview since she was selected by John McCain as his running mate at the end of August, she seemed at times lost for words and not all those she spoke fitted together.

The financial crisis means less attention will be paid to it than might otherwise have been the case. It could be, meanwhile, that Mrs Palin's unhappy performance will lower expectations ahead of her encounter with Senator Joe Biden at the vice-presidential debate in St Louis next Thursday.

It remains possible that the CBS interview will be known as the moment when the high gloss that Mrs Palin wore upon her selection before the Republican convention – burnished by her performance in St Paul – began to fade.

Even as members of the American media strive to avoid appearing snobbish or elitist in their treatment of Mrs Palin, most commentators seemed unable to disguise their sheer consternation at a performance that at times seemed worthy less of a candidate for vice-president than for school president. "Marginally responsive," was the gentle verdict of the Los Angeles Times after watching the interview of Mrs Palin by Katie Couric, the anchor of the CBS Evening News, shown on Wednesday and Thursday. The influential blogger Andrew Sullivan complained that the Governor was skittering not between "talking points" but "babbling points".

At the debate in St Louis, Mrs Palin will need to be better prepared and more articulate. Especially surprising, perhaps, was her difficulty with a question that they could have seen coming regarding her repeated assertions that the proximity of Alaska to Russia gives her foreign policy experience. What did she mean, Couric asked?

"That Alaska has a very narrow maritime border between a foreign country, Russia, and on our other side, the land boundary that we have with – Canada. We have trade missions back and forth. We – we do – it's very important when you consider even national security issues with Russia as Putin rears his head and comes into the airspace of the United States of America where – where do they go? It's Alaska."

She did not fare better when asked why the banking bailout package was important. Mrs Palin said it was about healthcare reform. She added: "Um, helping, oh ... it's got to be all about job creation too. Shoring up our economy and putting it back on the right track."

Couric, neither aggressive nor patronising, asked Mrs Palin about Mr McCain's record of supporting deregulation and what examples she could give of the senator supporting oversight of the financial sector. She suggested failed mortgage lenders Fannie Mae and Freddie Mac, but Couric wanted another. "I'll try to find some," the Governor said, "and bring them to you."

Debate has been raging about the unusual protective handling of Mrs Palin by Mr McCain's team. On Thursday, she took questions from a few reporters at Ground Zero, the first such encounter. The Katie Couric interview came after sessions on ABC and Fox News. Otherwise, she has largely been kept in a box.

This may have been a disservice to the Governor if it has denied her the chance to get accustomed to press attention. She seems drained of confidence.

Over Alaska-Russia, Mrs Palin almost came unstuck entirely. She struggled to describe the media reaction to her claims. The word she apparently sought was "caricature", but she couldn't summon it. "It – it's funny that a comment like that was – kind of made to – cari – I don't know, you know? Reporters ... "

"Mocked?" Couric asked.

"Yeah, mocked, I guess that's the word, yeah." The mockery may have only just begun.

The Couric interview: Who said what

Couric: You've cited Alaska's proximity to Russia as part of your foreign policy experience. What did you mean by that?

Palin: That Alaska has a very narrow maritime border between a foreign country, Russia, and, on our other side, the land-boundary that we have with Canada. It's funny that a comment like that was kinda made to ... I don't know, you know ... reporters.

Couric: Mocked?

Palin: Yeah, mocked, I guess that's the word, yeah.

Couric: Well, explain to me why that enhances your foreign-policy credentials.

Palin: Well, it certainly does, because our next-door neighbours are foreign countries, there in the state that I am the executive of.

Couric: I'm just going to ask you one more time – not to belabour the point. Specific examples in his [McCain's] 26 years of pushing for more regulation.

Palin: I'll try to find you some and I'll bring them to you.

Couric: In preparing for this conversation, a lot of our viewers ... and internet users wanted to know why you did not get a passport until last year. And they wondered if that indicated a lack of interest and curiosity in the world.

Palin: I'm not one of those who maybe came from a background of, you know, kids who perhaps graduate college and their parents give them a passport and give them a backpack and say go off and travel the world. No, I've worked all my life. In fact, I usually had two jobs all my life until I had kids. I was not a part of, I guess, that culture.