From stalled Mexican walls to Brexit chaos, we are seeing across the globe that good policy is not necessarily driven by popular opinion.

A recent Australian National University survey shows that just three out of every 10 Australians now believe the country needs more people.

As Australia debates its migration policy ahead of the next federal election, the ANU research indicates a decline in support for population growth.

More than 2000 adults were asked late last year whether they thought the country needed more people.

While the survey showed Australians appreciate the cultural diversity of the nation, only 30.4 per cent of respondents believed Australia needed more people, compared to 69.6 per cent who felt the country did not.

This suggests support for a big Australia has fallen since a similar question was asked in 2010, when 45.8 per cent of respondents felt the country needed more people.

The 15 per cent drop was largely attributable to falling support levels among men, who were still more likely than women to think Australia needed more people, the survey says.

Australians aged 25 to 34 had the greatest levels of support for an increased population, with 42.2 per cent in favour of growth.

People with higher levels of education and those born overseas — particularly migrants from non-English speaking countries — demonstrated strong support for a bigger population.

Greens voters were most likely to think Australia needed more people.

Coalition voters had the lowest levels of support of the major parties, with Labor voters somewhere in the middle.

According to the survey, the reasons for the drop in support were the high cost of housing, overcrowding in major cities, bad traffic and job security issues.

But here’s the rub. These reasons don’t really stand up to closer scrutiny.

The cost of housing, for instance, is driven by multiple factors of which migration is a minor one – and is also undergoing a downturn currently.

The gripe that “our cities are too crowded and there is too much traffic” is really a reflection of a lack of infrastructure planning and the building of it not keeping up.

Thirdly, the idea that we should train Australians for jobs instead of foreigners is laudable but it ignores the fact that immigrants are mostly brought in to fix dire, current shortages and that they actually boost the economy and create more jobs.

But the underlying issue here is that successive governments have not come up with a coherent long-term population policy.

They have fiddled around with skilled migration and temporary visas. They have been happy to take the cash international students bring with them without forging solid pathways to permanent residence for these people.

In an election year, there will be plenty of people using the migration debate to push their own agendas.

But it was interesting that the survey found that the more educated a person, the more likely they were to be accepting to migrants.

Maybe this is because educated people understand that Australia was built on successive waves of migrants; or because people with lower levels of education feel more vulnerable.

With a bare-knuckle election campaign on the horizon, there is a real prospect of ugly, dog whistle politics coming into play and migrants coping the blame for all of society’s problems.

When it comes to people who truly understand our history, the complexities of forming population policy, as well as the contributions migrants make to our society and economy, especially in light of our ageing population, we are in short supply.