When US President John F. Kennedy approved the Bay of Pigs invasion in 1961, he relied on advice from his staff, the defence force and the secret service. Nobody dared to voice any doubts this military attack on Cuba would be a success.

Still, it turned out to be a complete disaster. But at least Kennedy learned a lesson. From then on, he always encouraged dissent before making big decisions. This probably helped prevent a nuclear war in the Cuban Missile Crisis a year later.

The Kennedy example is used in the free online course OpenMind. Started by US psychologist Jonathan Haidt, the platform aims to restore respect and civility in debates. It does so by teaching the value of constructive disagreement.

Haidt spoke at a couple of events in New Zealand last week, which the Initiative supported. What he presented was a grim picture of politics, especially in the US. There, the polarisation has reached such levels that Democrats and Republics can barely talk to each other anymore. They understand each other even less.

As Haidt explained, there are many reasons for this breakdown in cross-party dialogue. Donald Trump is as much a cause as he is a symptom of the underlying malaise.

American society has forgotten how to deal with conflict. It starts early. Children are bubble-wrapped and cotton-wooled by their helicopter parents. There is no more free play without adult supervision. Children never learn how to settle differences with their peers on their own. Haidt writes about this in his latest book, The Coddling of the American Mind.

‘Social’ media then hampers their psychological development further as teenagers, not least by locking them (and their parents) into their respective filter bubbles.

At university, students then demand to be protected from uncomfortable views. They will call for ‘trigger warnings’ before encountering ideas that might be upsetting. ‘Safe spaces’ let them withdraw from anything distressing.

The psychological harm to the generation growing up like this is enormous. Haidt has documented the increase in mental health issues in young Americans.

Harm is not only done to the young people themselves but also to the wider society. It breaks down the social fabric. Political polarisation results from these developments.

New Zealand may be a few years behind these American developments, as Haidt pointed out, but we are not immune.

And thus, let us celebrate the relative civility of our domestic politics and defend robust and constructive debates.

You can check out how open-minded you are on Jonathan Haidt’s OpenMind platform.