Hanson, under pressure of failure, has lost the plot

Instead, it has exposed the party's exceptional vulnerability. On Saturday the party won just half the share of the vote that it won in the WA election of 2001.

In 16 years, its voter support in that state fell from 9.5 per cent to 4.7 per cent, according to the two-thirds of the vote counted by late Sunday.

Pauline Hanson was supposed to be riding the same tsunami of nationalist populism that carried Donald Trump to the White House.

Instead, she was left making excuses and blaming the voters: "People ask me about preferences and they don't understand the voting system, the preference system, and the preferences. I think that's where most of the damage has come from."

This is desperate stuff. Until now, populists only ever blamed the elites. They don't blame the people.

Unshakeable faith in the common sense of the ordinary people is the very definition of populism. Hanson, under pressure of failure, has lost the plot.

What happened?

First and foremost, One Nation forgot its essential character as a protest party.

Its entire raison d'etre is to register a protest vote against the main parties, to express the people's disgust at the political establishment.

Instead, One Nation did a deal with one of the main parties. Worse, it was with the ruling party. It made Pauline Hanson look like a close partner of the establishment.

Why on earth did One Nation agree to swap preferences with the Liberals, the party of Premier Colin Barnett?

Simple. It was a lunge for power. One Nation wanted more spillover preference votes, even if they came from the devil himself.

The party sold its soul for power. But it was far worse than a standard Faustian bargain. One Nation sold its soul, yet didn't win any temporary advantage. It ended up powerless as well as soulless.

At the campaign's outset, a Newspoll gave One Nation 13 per cent of the vote. In the final 10 days of the campaign, a Galaxy poll found that this had fallen to 9 per cent.

This timing is important - the party's vote slumped well before Hanson uttered her controversial comments about vaccinations and other matters.

One Nation was indeed punished for its deal with the Liberals.

Hanson might be right that the people don't understand the mechanics of the preferential voting system, but it turns out the people understood the meaning of the preference deal perfectly well.

The second thing that went wrong for One Nation was that Hanson opened her mouth.

"When she's been silent," remarks a leader of a major party, "people think she's on their side. But every interview turns out another batshit crazy idea, and people can see that she's not on their side, she's just batshit crazy."

Her anti-vaccination comments fall into this category; so do her comments exonerating Vladimir Putin from any responsibility for killing the 38 Australians on MH17.

One remark that's not in the crazy category, however: Hanson's promise to help WA win a bigger share of GST revenue even if it were at the expense of her home state of Queensland - and then denying that she'd said any such thing.

It's merely the double-dealing and deceit that voters expect from the major parties. But not from Hanson, supposedly an "authentic" person.

When she was being "authentic" she was exposed as crazy; and when she was being a shrewd political player she was judged to be inauthentic, a sell-out.

Yet it'd be wrong to write Hanson off. She has lots of time to the next federal election, likely more than two years. If she uses WA as a learning experience, she can recover.

Her support in Queensland is much stronger, and a looming state election there will give her another chance to prove herself relatively soon.

But Hanson's greatest asset is the inevitable disappointments that the main parties will be offering in the meantime. Hanson just has to remember that she's a protest politician, and the major parties will doubtless send plenty of protest votes her way.