It feels like a turning point has finally been reached on party reform after Labor's farcical preselection process derailed its campaign in Western Australia, writes Barrie Cassidy.

West Australian Senator-elect Joe Bullock could well gain unwanted notoriety as the catalyst for change in the ALP, the man who finally forced the party to do something about a preselection process that throws up somebody like him.

That would be some contribution to the party's history.

The ALP has been getting away with a self-indulgent, narrowly based and totally flawed preselection process for senators for decades. For every talented union official who manipulated the system and got elected, there was a drone to match.

Consider how Bullock got there. He once ran for a winnable seat in the West Australian Lower House, and got thrashed.

This time, as head of one of the two biggest Labor-affiliated unions, the Shop Assistants, he did a deal with the head of United Voice that gave him the number one spot ahead of Senator Louise Pratt, and in return he allowed United Voice to choose the replacement for Senator Chris Evans.

No more than four or five members would have influenced those decisions.

Nobody would have noticed had it not been for the extraordinary nature of last week's Senate vote. Ordinarily, at general elections, unlike in the Lower House, nobody has any idea who the Senate candidates are. They vote along party lines.

But this time the candidates couldn't escape the spotlight. That's why Greens Senator Scott Ludlam did so well. He boosted the Greens vote because he was an identifiable and attractive candidate for the left of politics.

Bullock, on the other hand, when he did emerge from obscurity, not only failed to convince anybody of his current credentials, but was haunted by his past.

Late in the campaign, it was revealed he was once convicted of unlawful assault; and then, off the back of that, his speech last November to a conservative Christian group was leaked. In that address, he mocked his own party and, in particular, his running mate Senator Pratt, questioning her sexual preferences in the crudest of terms.

Even in an age when bigotry is apparently making a comeback, his words left his colleagues stunned.

Maybe it will take such an example to get Labor to the line on serious party reform. It does now feel, as Laura Tingle observed in the Financial Review this week, that a turning point has been reached. United Voice appears to have recognised as much, with the union publicly calling on Bullock to resign from his Senate post on Thursday afternoon.

Opposition Leader Bill Shorten is proposing to get rid of the requirement that candidates have to be union members. That is a very modest start, and that rule hasn't been enforced for years anyway.

Party insiders go on about boosting membership. The key to a more credible future, however, rests with a modern preselection process that gives those members a genuine say in who should sit in the Parliament.

Listening to powerbrokers talk about preselections in safe seats is a disturbing experience: "That seat's for the Shoppies, the Missos got the last one." The situation won't be genuinely fixed until the trade union bosses and the faction leaders are unable to predict the outcome of these contests.

An experiment in party democracy won't necessarily and immediately turn up better candidates. But over time, they will be more representative of the country as a whole.

Some worry that the trade unions will be driven away from the ALP, taking with them their money and their considerable organisational skills.

There is a sense in some quarters that the party is deserting them in their hour of need. Not only will the Royal Commission bring them under sustained attack, but more broadly, globalisation, free trade and a dying manufacturing base threatens their membership and their relevance.

But it shouldn't come to that. Trade unions were the very basis of the original Labor Party. Whatever new system is devised, there is little chance the party will overshoot and leave the unions entirely without clout and influence.

At some stage, the benefits of reform have to be weighed up against the negatives. And when that judgment is made, the party should keep in mind that there are 1.8 million trade unionists and yet the ALP has just 44,000 members.

Influence should be in line with that reality.

Barrie Cassidy is the presenter of the ABC program Insiders. View his full profile here.