Australian politics has entered a new era.

The days when Labor and the Coalition could assume they would attract almost every vote are fading. Australians are increasingly willing to support independents and minor parties when they believe their concerns are no longer being heard.

Among the beneficiaries has been One Nation.

Whether measured by election results or opinion polling, Pauline Hanson's party has demonstrated an ability to attract a significant bloc of Australian voters over many years. That presents a question both major parties should be asking.

Why are Australians continuing to support One Nation?

Instead, political debate often takes a different direction.

Labor regularly attacks Pauline Hanson and her party. Coalition leaders have also criticised One Nation, urging conservative voters to remain with the Liberal and National parties.

Political disagreement is an essential part of democracy. Parties should vigorously challenge each other's policies.

But there is an important distinction between debating policies and dismissing the appeal of a political competitor.

Every Australian who votes for One Nation is also making a statement about the major parties.

Some may be concerned about the cost of living. Others worry about immigration levels, housing affordability, energy prices, government spending or the pace of social change. Still others simply believe the traditional parties no longer represent their interests.

Not every One Nation voter shares the same motivations.

However, together they represent a sizeable group of Australians who have decided to look beyond the two-party system.

That should prompt reflection rather than ridicule.

If voters are leaving, the first question should not be, "How do we attack the party they chose?"

It should be, "Why did they leave us?"

History suggests that minor parties rarely grow because they are criticised too little.

They grow because enough voters conclude the established parties are no longer listening.

This is not unique to Australia. Across many established democracies, traditional parties have seen support fragment as voters seek alternatives they believe better reflect their priorities.

Australia is experiencing the same phenomenon.

The response from Labor and the Coalition will help determine whether that trend continues.

If the answer is simply to dismiss One Nation as unworthy of consideration, there is a risk that millions of Australians who vote for the party will feel dismissed as well.

That is unlikely to persuade anyone to change their vote.

Democracy is a contest of ideas, not a contest of insults.

Major parties are free to criticise their competitors. Indeed, they should challenge policies they believe are flawed.

But political competition is rarely won by dismissing competitors.

It is won by persuading voters that their concerns have been heard, understood and addressed.

Perhaps the rise of One Nation is not merely a challenge for Pauline Hanson.

Perhaps it is a message for Australia's major parties that many voters are still waiting to be heard.