It is a double-edged question. To what extent can a liberal democracy tolerate the bigotry espoused by Trump? Equally to what extent can a liberal democracy tolerate a religion (or sect of a religion) that espouses repression of women and homosexuals, death for adultery and apostasy and amputation for thieves?

After all, both Trump and some Islamic sects are seeking political power. When an extreme form of Islam (or any other religion) attains power in a given territory, liberal democracy is dead. Iran is a good example, as is the territory now held by Islamic State.

It is the end of liberal democracy because it demands total compliance.

Maybe if Trump attained political power, liberal democracy would similarly wither in the US as it did in Germany between the wars. In a way, Trump is demanding compliance – compliance to any religion other than Islam.

In short, how much intolerance can we tolerate?

John Stuart Mill in On Liberty helps. He said society should not repress speech because it is only through dissent and free speech that truth can be ultimately revealed.

So the reason we have freedom of religion is because it is a sub-set of free speech. Only when people are free to espouse whatever religious dogma they want can it be exposed as truth or, more probably, falsity.

Mill would argue we should not stop people from asserting that the law should be changed to make, say, homosexual acts punishable by death or adultery by stoning, however repugnant that might be to the vast majority of people.

Mill wrote: "The only purpose for which power can be rightfully exercised over any member of a civilised community, against his will, is to prevent harm to others. His own good, either physical or moral, is not sufficient warrant ... Whatever crushes individuality is despotism, by whatever name it may be called and whether it professes to be enforcing the will of God or the injunctions of men."

The difficulty arises when those who want to prohibit some actions which cause no harm to others get elected to a position of power where they can enforce their views.

Do we just hope that if we permit freedom of speech, that enough people will ensure that those with odious or repressive views simply do not get into power, either elected or through force. It seems there is little alternative.

If so, it is imperative that freedom of speech is not curtailed. Only when the odious is expressed can it be countered.

For example, it is excellent that Trump has not felt compelled to withdraw his comments that Muslims should be prevented from the US. It is excellent that having thought this, that he expressed it. He obviously thinks it is a good idea. Only when his view is in the open can it be countered – and countered in a way that prevents him from attaining power.

How much better that US voters know his mind than he get elected without them knowing it. If we find that a huge number of people agree with his odious proposal, it only shows that the rest of the people need to get a bit more active with their friends, family and acquaintances to persuade them otherwise.

Now let's return to people who hold positions of authority in Islam, Mormonism, Christianity and other religions. A legitimate question for liberal democrats (in the lower-case sense) to ask them is: if you had the power, to what extent would you exercise that power over individuals who were doing no harm to anyone else, but were offending your religious principles?

Henry VIII, for example, would say something like: if you continue allegiance to the Pope and do not recognise me as the head of the church in England, I will chop off your head. Some present-day Protestant fundamentalists similarly urge violence against those they disagree with.

The present day Archbishop of Canterbury, on the other hand, would no doubt say he would restrict his action to persuasion by words alone.

Similarly, an ISIS leader would be into head chopping, whereas the Grand Mufti of Australia, Ibrahim Abu Mohammad, has said, "Islam unequivocally condemns all forms of violence. For a long time now there has been a comprehensive theological refutation of the claims made by groups like ISIS, by Muslim scholars around the world."

So, there is nothing to fear from tolerating the profession and practice of religions which in turn tolerate the profession and practice of other religions. Indeed, it would be better not to think of it in the context of religion, but of organisations. Moreover, the "organisation" should not be seen as the whole religion, but as individual parts – sects, parishes, churches, mosques, or whatever.

Let persuasion and freedom of speech determine if anyone wants to adhere to any of them or none.

To return to Mill. He championed the liberty of thought and opinion; the liberty of tastes and pursuits; and the liberty to join other like-minded people for a common purpose that does not harm anyone else. Joining a religious organisation fits the last, provided of course, the organisation does not espouse violence or aim to recruit people to its violent cause.

So a liberal democracy should tolerate free speech right up to the point of exhortation to violence and recruitment to violent organisations.

Viewed like that the idea that the whole of Islam needs "enlightenment" or a "reformation" as suggested by former prime minister Tony Abbott does not make sense. Indeed, it does not fit with the very ideals of liberty and enlightenment that he purports to espouse.

Similarly, Trump's idea that you can shut out people who propose no violence or harm is itself harmful and violent. Moreover, it should persuade people that he is not fit for power.

www.crispinhull.com.au