Why are we sending our forces?

The immediate reason is that the Islamic State's atrocities against enemies and civilians are so appalling that the world cannot sit back and watch. There are also concerns that IS can reach across the world to supporters here in Australia, as recent arrests in Sydney and Melbourne indicate.

Ground crew prepare an RAAF E-7A Wedgetail Airborne Early Warning and Control aircraft.

On a deeper level, Islamic State, also known as ISIL, threatens the stability of the region if it inflames Sunni extremism in countries such as Saudi Arabia and exacerbates sectarian tensions in Shiite power Iran.

Might Australia be drawn back into a lengthy war in the Middle East?