After yesterday, the prime minister and her team might be wondering whether it would have been better to have spent the week debating the carbon pricing scheme in parliament, rather than venturing out into shopping malls.

The House of Representatives is a far more controlled environment, and there’s not much evidence the opposition would’ve been able to ask any particularly acute questions, both because of its seeming lack of policy grasp, and because, inevitably, at least two question times would have been curtailed by censure motions. Sometimes — as Kevin Rudd showed in his health debate last year — it’s a good idea to give Tony Abbott exactly what he asks for.

The woman who tripped up the prime minister yesterday was Julia Gillard’s nightmare brought to life — a voter uninterested in actually hearing what the prime minister had to say, and simply concerned to tell the Prime Minister she was a liar.

If Abbott trying to talk down the economy by warning of economic catastrophe following the carbon price is a reflection of his political skills, the prime minister’s problem with her credibility is the other component of his campaign against the carbon tax. But it’s one solely of the government’s making.

The prime minister has had five months to find the right response to the question about her pre- and post-election positions on carbon pricing, and she’s yet to do so. Her preferred response is a complex mishmash of explanations about changed circumstances and always wanting a carbon price, and merely serves to reinforce perceptions that she has no credibility and isn’t sure what she believes in.

The only thing she’s now got going for her is the Iron Lady stuff, designed to remedy the latter problem by showing voters she’s prepared to persevere with policies she believes in even if it damages her politically. It’s a long-term strategy — necessarily, because it has to reverse current voter attitudes, whereas everything Abbott says is designed to reinforce voter attitudes.

That’s not to say it can’t work. Margaret Thatcher had plenty of run-ins with truculent voters herself, but it didn’t do much harm. And Bob Hawke didn’t just trip over cables in shopping centres — in 1987 he shocked commentators by going on television to tell Australians he’d rather lose office than give up his government’s economic reform program. But it strengthened his credibility with voters in the run-up to an election against John Howard, who was trying to woo the electorate with a massive tax cut bribe.

But there isn’t much evidence so far that the Labor brains trust has lifted its game sufficiently to reverse the comprehensive collapse of the prime minister’s credibility with voters. And conducting an election-style campaign that automatically elevates her opponent and focuses more attention on personalities than policies isn’t helping.

Still, at least she’s wrecking herself in the cause of a worthwhile, if not brilliant, policy. Kevin Rudd wrecked his prime ministership over the CPRS, and that was a dog.