When the chattering classes get too far out of sync with ordinary people, there's trouble ahead.
We Brits know that, having witnessed the disaster of Brexit. Americans might know it having witnessed the disaster of Trump.
Take immigration. For decades, any debate about immigration in Britain was closed down.
The signs of unease among ordinary working people - who once were called the working class - were just dismissed as the racism of the stupid and the ignorant.
When trade union members marched to the chant "I'm dreaming of a white Christmas" in the 1960s, it was rightly condemned. It was racism impure and simple.
But an underlying anxiety festered over the decades, only to burst out after Tony Blair's decision to allow mass immigration to Britain from the new members of the European Union, Poles in particular.
I welcomed this wholeheartedly. It made London even more cosmopolitan and exciting.
It had a huge benefit for nice middle-class people like me: we could afford servants, not that we called them that. They were cleaners and gardeners, paid a fraction of the unaffordable rates the native British demanded.
In my nice suburban home in leafy London, we employed a cleaner from Krakow - Helena, the cleaner, as she was known. Helena built up a business. She employed Polish painters who painted my house at a quarter of the previous British rate. Even at her cut-throat prices, Helena sent enough money back to Poland to build a house for her mother.
We in the chattering classes thought immigration was brilliant.
But out there, in that other world of insecurity and scraping a living, many thought immigration was terrible.
In our nice areas we lolled in the back of cheap taxis driven by Poles, while in deindustrialised Old South Wales, where I came from, redundant factory workers and miners trying to make ends meet by driving cabs faced cut-price competition.
The chattering classes dismissed the objections to immigration as ignorant and stupid - but the objectors had their revenge when they voted for Britain to leave the European Union.
It was, I think, partly an unfocused reaction by those on the outside against those who presumed to tell everybody else what to think.
Protest down the centuries has often been unfocused, sometimes as an inchoate rage - but that shouldn't make it despicable or dismissible. The 19th-century British and Irish rioters, by the way, often ended up as transported pillars of Australian society.
Which brings me to the anti-lockdown protests.
There is no doubt a mixture of motives at work: some far-right crazies getting daft ideas on the internet, some old hippies who think "nature" doesn't believe in vaccines - but also some who are simply hurt by the current severe lockdown of the economy.
It is easy to sneer at the protesters. And it is easy and right to condemn the violence.
But protests do not need neat manifestos of policies with dot points to mean something. They are a symptom of real and deep anger.
If politicians in the comfort of the metropolitan bubbles dismiss the anger and move on quickly, that anger will come back and bite them.
Take it from a Brit.
- Steve Evans is a Canberra Times reporter.