Over the past three years, large numbers of Australians have chosen to leave the freedom, opportunity and safety of our community to enter the abyss of sectarian war and violence in Syria, northern Lebanon, and most recently, Iraq.

The numbers are frightening. Over 200 Australians are estimated to have either fought with or provided direct material assistance to groups such as the Islamic State of Iraq and al Sham (ISIS) and Jabhat al Nusra (an al Qaeda affiliate), according to several media reports citing intelligence and police sources. A few are thought to have returned home to Australia.

Stark as they are, the numbers alone aren't what is truly frightening. The game changer for Australia's security at home are the skills and experience gained. Australians are gaining combat experience in close-quarter fighting, the use of explosives and opportunities to forge closer linkages with ideologically-radical and battle-hardened militants. Australia's first ever known suicide bomber is suspected to have died in an attack in Syria last November. Folks like Mamdouh Habib and David Hicks were rank amateurs compared to the current crop of Aussies waging jihad.

So what should Australia do?

The size and span of this enduring threat demands a completely new approach for our counter-terrorism effort, both here and offshore.

Our police and intelligence agencies have achieved many successes over the past several years. Some of this has been openly recognised (such as the PENDENNIS and NEATH investigations), but some results must necessarily remain unacknowledged. There have been, nonetheless, occasional points of friction between agencies. Thankfully, the domestic threat environment has been sufficiently low to absorb the occasional disagreement among friends. Not anymore.

Blood spilt in homeland attacks has forced our American and British allies to quickly learn some pretty tough lessons. A trend amongst US and UK establishments has been the development of inter-agency structures for operational and tactical-level efforts, both at home and abroad. Such structures have challenged and overcome entrenched bureaucracies to achieve unified effects which harness capabilities, skills and single-agency authorities. Many of these inter-agency efforts have been driven by civilian intelligence and law enforcement, with the military serving as only a supporting or enabling element. 

In Australia, our experience is relatively immature in this area. Some arrangements which could be perceived as joint or inter-agency (such as our recent efforts in Afghanistan or perhaps the Joint Counter-Terrorism Teams) have lacked a binding command and management framework. Operational and tactical-level decision-making has, by default, been by consensus. This is not a good recipe when entrenched bureaucratic mindsets are confronted with complex temporal decision making.

Though politically contested, Operation Sovereign Borders (OSB) has been a serious attempt at enacting a larger joint inter-agency approach evolving from the success of Border Protection Command (BPC). OSB and BPC have striven to achieve unity of command under law as well as unity of effort — very important principles in complex problem solving.

Learning from our allies and OSB, the Government should consider establishing a Joint Inter-Agency Task Force (JIATF) to address the urgent Australian jihadist threat. The JIATF's mission would be to gather and analyse intelligence, liaise with allied and other foreign partners and take law enforcement action against Australian jihadists (it should also ensure that things like this don't happen again). At home, increased messaging to deter and prevent travel, and an invigorated effort to counter violent extremism, would be essential. 

To work, the JIATF must have a binding command and management mechanism. The JIATF's senior leaders must be given the legislative authority to give direction and make decisions for all the participating agencies. Furthermore, operational funding should be provided directly to the JIATF and not be 'filtered' by parent agencies.

Given the threat, it seems appropriate for the JIATF to be led by a senior and experienced police officer. Heavy-hitters like NSW Police's Deputy Commissioner Nick Kaldas (who in 2009  was chosen to lead the UN enquiry into the assassination of Lebanese Prime Minister  Rafik Hariri) or Victoria Police's Deputy Commissioner Graeme Ashton (formerly of AFP; he led the 2002 Bali bombing investigation) would be excellent candidates with the respect, strong leadership and wily experience essential to overcoming any Canberra obstinacy.

Several deputy commanders  would be appropriate, covering intelligence (ASIO), policy (Attorney-General's Department) and diplomacy (DFAT). Besides these, agencies of the Australian Intelligence Community, Australian Crime Commission, federal and state police, the ADF, Customs, AUSTRAC and Immigration should all provide staff for the JIATF. The Inspector-General of Intelligence and Security and the Australian Committee for Law Enforcement Integrity could be given additional resources to enable oversight. 

Some JIATF areas could also be opened to Indonesian and New Zealand participation. The returnee threat arguably will affect Indonesia more acutely than Australia. It would be a chance for Australia to practically help Indonesia provide for its security, harnessing our allied intelligence and diplomatic relationships. Since 2012, New Zealand has been a full member of the Australia-New Zealand Counter Terrorism Committee (ANZCTC).

The strategic warning is clear. Australia must act decisively. The lessons learned in blood by our allies in homeland attacks since 9/11 behove us to dispense with business-as-usual approaches. Innovative responses are what Australia needs, not decision by committee. These responses mustn't only understand current circumstances, but envisage a future in which dozens of hardened fighters return to Australia and Southeast Asia.

We don't want Syria and Iraq to be a sanctuary and staging base for a new wave of global terrorism. We must harness all national resources in a binding joint inter-agency effort here and offshore to defend Australia and ensure extremist skills gained on Syrian and Iraqi battlefields don't manifest themselves in terrorist attacks on home soil.