Let the voter beware. We may be in a "celebrity" age but personality parties, based around a "name" implode, explode, or fizzle. In the past few years, we've seen them do all three.

On Thursday came the latest episode in the One Nation soapie, when Senator Brian Burston announced he was leaving the party to sit as an independent. Pauline Hanson had effectively tossed him out anyway.

Only a couple of weeks ago, after their spectacular falling out over company tax cuts, Senator Burston was declaring Senator Hanson had her moods and he hoped they'd make up. She responded by saying he should give up his seat.

So now Senator Hanson is down from having four Senate numbers after the 2016 election to two, with multiple bizarre twists in the course of the shrinkage. The combination of a capricious leader and eccentric and accident-prone followers has cost the party what was a pivotal power position in the Senate.

On the face of it, Pauline Hanson and Nick Xenophon have little in common. Senator Hanson's politics operate, in considerable part, around the extremes; she taps into some dark places and often generates outrage. Ex-senator Xenophon hoovered up those disillusioned with the major parties, but from a centrist position.

In terms of leadership style, however, we can see a certain commonality. As a leader, Nick Xenophon was autocratic — albeit his was a much smoother, smiley face of autocracy than Senator Hanson's. As in any party based around a personality, it was all (or at least mostly) about him.

Xenophon's flaw was overreach

One paradox of leaders of personality parties is that while they attract voters and so can get others elected, this can be their downfall, because they are by nature loners not team people.

Like Senator Hanson, Mr Xenophon ended up harming his creation. In his case, the flaw was overreach. Consider what might have been if Mr Xenophon had not left the Senate for his ill-fated bid to be, if not the king, at least the kingmaker in South Australian politics (his SA-BEST won only two upper house seats in the March state election).

He would still be leader and chief negotiator for the group, which started this term with three votes in the Senate. He would have lost one senator, Skye Kakoschke-Moore, to the citizenship crisis, but her replacement, Tim Storer would probably be part of the team, instead of sitting as an independent. Before the High Court elevated him, Senator Storer had fallen out with the party when he wasn't given the casual vacancy Mr Xenophon's departure created.

If the party presently had three senators — rather than two — it would still have a veto power over legislation that Labor and the Greens opposed.

Post Xenophon, the old "Nick Xenophon Team" has become the Centre Alliance — Mr Xenophon himself had always said the name would be de-personalised — and the one-time leader has no role in it.

Contacted this week, Mr Xenophon sent a text saying he was "not making comment on anything political — my former colleagues are more than capable". It was a far cry from when he quit the Senate last year, promising to keep a hand and a voice in what was happening in federal politics.

He's concentrating on building his legal practice. Some believe he might have another shot at the Senate; others say that is out of the question but he could end up in State Parliament. He has not even appeared in the campaign in the Adelaide Hills seat of Mayo where the Centre Alliance's Rebekha Sharkie, another citizenship casualty, is fighting for her political life.

Windsor, McGowan, Wilkie all did it

The battle in Mayo, while important for Centre Alliance, is more interesting on other grounds. It is a test of the ability of a crossbencher who wins a seat from a major party to entrench themselves.

Tony Windsor did it in New England (won from the Nationals). Cathy McGowan has done in Indi (seized from the Liberals), as has Andrew Wilkie in Denison (wrested from Labor).

Ms Sharkie in 2016 defeated a Liberal who was on the nose; in the byelection, she is up against high-profile Liberal candidate Georgina Downer, daughter of former foreign minister Alexander Downer, who occupied the seat from 1984 to 2008.

Two recent polls have put Ms Sharkie ahead of Ms Downer 58-42 per cent in two-party terms. It's a long time until election day (July 28), but if Ms Sharkie does regain her seat, perceptions about her as a local member would likely have counted more than her party branding, despite what would be Centre Alliance's celebrations.

In terms of its Senate future, the Centre Alliance has some breathing space — its two senators, Stirling Griff and Rex Patrick, are long-termers and so don't face the people at the next election. But that election will be crucial for the party — to show it still has life, it needs to get a new senator elected (and it won't have the 2016 advantage of the smaller quota that applies in a double dissolution).

What used to be the Xenophon party will eventually fade away federally: the question is how long that will take. Its cycle will be rather longer and less spectacular than the personality-based Palmer United Party, which came and went in a single parliamentary term.

One Nation will also disappear

Pauline Hanson's One Nation, at least in its present form, will also disappear in the fullness of time. Senator Hanson, like the Centre Alliance senators, isn't up for re-election, so she will be around a while. But apart from in Queensland it will be difficult (albeit not impossible) for her to get anyone else elected under the larger quota required in the coming half-Senate election.

Personality-centred parties are different from more broadly based minor parties — the Greens and the now-defunct Australian Democrats — although the latter parties may be heavily identified with particular leaders.

Strong leaders, to whom the public relate, attract supporters to such parties (the Greens' Bob Brown; Don Chipp, Cheryl Kernot for the Australian Democrats). But these parties have firmer and deeper roots than the personality parties, so they survive well beyond an individual figure. Though the Democrats are gone, they lasted a generation, through several leaders.

Most small parties, whether personality-based or not, get their backing by tapping into the dissatisfaction felt by many voters with the major parties. The Senate proportional representational voting system means they can translate modest — in some cases minimal — support into maximum impact in the Federal Parliament.

Changes the Government has made to the Senate electoral system will put a check on that ability, but not wipe it out. In the years to come, mega personalities potentially will still be able to create parties in their image that become bright flames. But as with others before them, such parties would seem destined to be flashes in the pan.

Michelle Grattan is a professorial fellow at the University of Canberra and chief political correspondent at The Conversation, where this article originally appeared.