Originally published in The Australian, 1 February 2018

One of the current government’s great successes has been border protection policy. Given the scale of the people smuggling that had developed under the former Labor government, not even the original architects of border protection, John Howard and Philip Ruddock, thought it could be done. But very quickly, we stopped the illegal boats that had brought 50,000 uninvited people to our country and led to more than 1000 deaths at sea. And the boats have stayed stopped thanks to the government’s continued good work led by Home Affairs Minister Peter Dutton.

An even stickier problem than stopping the boats is stopping the jihadi fighters. It’s one thing to stop foreigners who’ve first flown to Indonesia and have no entitlement whatsoever to come to Australia. It’s another to stop Australian citizens from returning home even though they’ve taken up arms against Australian forces, fought against our way of life and may subsequently prove a deadly menace to their fellow Australians. Yet it is absolutely necessary to keep our people safe and that means keeping off our streets anyone who regards himself or herself as at war with Australia.

Late last year, ASIO boss Duncan Lewis told a Senate committee that about 85 Australians had been killed while fighting as terrorists in Syria and Iraq and that 40 Australian foreign fighters had already returned home but that about 110 Australians were still in the war zone. Most of the returnees, he stressed, had come back before the declaration of the Islamic State caliphate and were not now considered threats to security. And “every returnee” he said, would be closely scrutinised for prosecution and prison or “some form of diversionary programme depending on the circumstance of the individual”.

At one level, this is very reassuring. But for it to succeed our intelligence about Australian jihadis needs to be accurate, our airport security has to be fool-proof, our courts need to convict all the dangerous ones, and the “infidels-don’t-really-deserve-to-die” re-education has to work. It’s a lot to ask. And keeping in gaol people who think they have a religious duty to kill any or all of their unbelieving fellow Australians is very costly, especially if they have to be segregated from susceptible fellow prisoners to stop our gaols from becoming jihadi enlistment centres.

No one should assume that the fall of the caliphate has disillusioned its followers about militant Islam. Some years back, about 25 Australians went to Afghanistan to fight with the Taliban; and 19 of them were subsequently involved in terrorist plots after their return. Eleven of the 17 Bali nightclub terrorists had previously trained with the by-then-deposed Taliban and its allies. Even though the current conflict in the Middle East seems to be winding down, its “soldiers” are unlikely to abandon their allegiances any time soon and, back here, would be a much bigger potential pool of trained, battle-hardened jihadi warriors than ever before.

Almost on taking office, the Abbott government was focussed on counter-terrorism but dramatically ramped up its efforts after the caliphate urged attacks on Australians in mid-2014. In my time as prime minister, we established counter-terrorism teams at international airports, started to introduce biometric screening for travellers, boosted AFP and ASIO resources and personnel, made it easier to prosecute and convict potential terrorists, stripped welfare payments from security threats, and – importantly – legislated to strip terrorists who were dual nationals of their Australian citizenship because we didn’t want them back in the country they had betrayed. This is not controversial now; but it was at the time, even inside the cabinet.

As I said back then, “we’re trying to prevent people from leaving our country to become terrorists; we’re trying to prevent hardened terrorists from coming back; and we’re striving to lock up any that we can’t keep out”. But here’s the point: given the way Australian courts work, there’s no way all of them will be locked up; so now that they can be expected to return, we need better ways to keep them out. As I said in June 2015, “fighting with a terrorist group at war with Australia is the modern form of treason – and those who have left our country to fight against us may require a modern form of banishment”.

This is what now needs to be put in place: a way to stop terrorists returning even though they are solely Australian citizens with a normal right to be here. And there is a readily available overseas precedent. Since early 2015, the British government has been able to make court-supervised “temporary exclusion orders” against sole-citizens who have left the country to fight with terrorists and would pose a menace to the public if they returned. Last year the Home Secretary said that these TEOs had started to be used against some of the 1000 UK nationals thought to have been fighting for the caliphate and it’s time that the Australian government had the same power.

Not even the most diligent government with the best possible security services can guarantee to prevent all acts of terrorism. So far our police have been highly professional and luck has mostly eluded our local would-be terrorists; but we can’t count on always being lucky. Inevitably, the government will be held to account if and when there is a big terrorist atrocity here – and blame would be justified if there were any reasonable precautions that the government had failed to take. If keeping Australians safe requires periods of exile for a handful who no longer deserve to live amongst us, isn’t it the government’s duty to get it done?