Originally published in The Australian

France’s President Francois Hollande is absolutely right to describe the multiple, co-ordinated atrocities in Paris as an act of war. For more than 12 months, the self-styled Islamic State caliphate has been urging its adherents around the world (sometimes specifying Australia) to find unbelievers and to kill them.

The mass attacks in Paris, on top of the apparent downing of a Russian jetliner plus increasing suicide bombings in the Middle East, show this would-be terrorist empire is becoming much more sophisticated and capable in its campaign to murder anyone who does not share its fanatical beliefs.

It’s now obvious that even a small group of fanatics, ready to die themselves and prepared to kill others without mercy (the more, the better), can wreak massive damage on societies that are vastly more sophisticated but much less single-minded.

As long as substantial swathes of the Islamic world believe in “death to the infidel”, there will be more terrorist outrages — especially with a caliphate urging susceptible people to believe that, somehow, God is on their side.

Where fanatics can only access knives, handguns or shotguns, there will be more incidents like the attack at the Endeavour Hills police station in Melbourne, the Martin Place siege in Sydney or the killing of a police employee in Parramatta.

Where they can access semi-automatic weapons, there will be more atrocities like the mass killings in Paris.

And where they can access bombs and smuggle them into place, there will be more planes blown out of the sky as over the Sinai.

As long as some people fiercely believe that it’s morally right to kill any and all who don’t share their warped view of Islam, the scale and spread of the carnage will be limited only by their access to weapons and ability to deploy them.

Islamic State cannot be contained; it has to be destroyed — because as long as it exists, the killings will continue. The more it grows, the worse the killings will become.

This means much more resolve to protect our way of life and to defend our values.

It means the most vigorous measures to render harmless Islamic State operatives wherever they are; and the most concerted support for decent Muslims trying to reclaim their faith from the fanatics who kill in its name.

It means much more readiness to fight Islamic State abroad as well as at home; and it means calling out any Muslim leader who makes excuses for terrorism.

The rise of Islamic State has prompted some welcome rethinking of what Islam really means.

Egypt’s President Abdel Fattah el-Sisi told the imams of Al-Azhar University in January that Islam needed a “religious revolution” to purge itself of false ideas that were causing carnage.

Malaysia’s Prime Minister Najib Razak has said that Islamic State, or Daesh, is against God, against Islam and against our common humanity.

We need to engage much more with decent, humane Muslims who accept religious freedom; and rather less with those who always see Islam as the victim.

Under my prime ministership, Australia was quick to recognise the danger of Islamist extremism. We raised the terror threat to high shortly before the first domestic brush with terrorism. We strengthened security at our Parliament House shortly before the attack on the Canadian parliament.

We offered the US military backing as soon as the caliphate was declared.

We swiftly deployed a powerful air contingent to the Middle East, gave special forces support to Iraq and then a taskforce to train the Iraqi regular army.

We increased funding to the Australian Federal Police and ASIO, and gave our security agencies stronger powers to deal with potential domestic terrorists. The legislation I flagged to strip terrorists who are dual nationals of their Australian citizenship and to outlaw advocacy of genocide has now been introduced to the parliament.

No one should want to rush more forces to a region that’s a witches’ brew of danger and complexity and where nothing ever has a happy ending.

No one should lightly deal with regimes that act as recruiting agents for terrorism.

Yet it seems that no one can now avoid the choice between bad and worse, especially when inaction is itself a choice. Especially in the wake of Paris and Sinai, it’s becoming clearer that an understandable reluctance to accept military casualties abroad could easily lead to more civilian casualties at home.

Preferably with Sunni states such as Turkey, Egypt and Jordan, as well as with the US, Britain and France, Australia should be prepared to contribute more to a military campaign to destroy this terrorist caliphate on the ground in Syria and Iraq.

This could involve less restrictive targeting rules for airstrikes and the deployment of special forces on the ground in support of local forces, similar to the 2001 campaign where the Northern Alliance defeated the Taliban in Afghanistan.

The G20 in Turkey is the obvious place and now is the obvious time to start to put an effective international military coalition together.