History is replete with war motivated by religious disagreement. One example is the centuries-long clash between the Catholic and Protestant variants of Christianity.

Religion remains a significant driver of conflict in some parts of the world today. But it seems that Catholics and Protestants, at least, have finally learned to live with one another.

Arguably, most westerners just don’t take religion seriously enough to kill and die for it anymore. But free speech may also have contributed to the truce.

Over several centuries, growing acceptance of free speech made it more and more possible for Catholics and Protestants to talk through their differences. Over the same time period, the incidence of armed conflict between them diminished.

Unfortunately, our ability to speak freely on religious matters may be at risk.

In the wake of the Christchurch Massacre, the government sought to extend our hate speech laws. The initial plan was to add a variety of identity characteristics – sex, sexuality and religion – to existing legislation. Threatening, abusive or insulting speech targeted at ethnic, racial and nationality groups has been banned since 1993.

That legislation was withdrawn following concerted opposition. Recently, however, Justice Minister Kiri Allen announced the return of hate speech legislation, albeit in a reduced form. Now, the government seeks only to add religion to the list of protected characteristics.

As hurtful as it is to be a target of hateful comments, there are sound reasons not to criminalise those who make them.

For one thing, ridiculing religious ideas themselves arguably insults those who believe them too. So scornful remarks about religious beliefs could easily run afoul of Allen’s new laws.

For another, the new legislation, if passed, might actually increase the likelihood of violence motivated by or against religion. People who don’t feel free to voice their hateful thoughts may be more likely to act on them.

But there is an even better reason to maintain the ability to freely express ideas, even awful ones. Untrammelled expression, as bruising as it can sometimes be, tends to bring people together in the long run.

Protestants and Catholics once regarded one another as heretics. They sought to censor one another on pain of death. Now, following a long period during which peaceful dialogue has been possible, it is not unknown for them to worship together.

Our legislators would do well to reflect on that.