As predicted by many people at the time, the invasion of Iraq was a humanitarian, legal, political and strategic disaster. It left a trail of death and destruction and millions of refugees. It undermined the role of international law and strengthened terrorism. Australia's role in the war raised serious questions of government honesty and accountability. If we do not learn lessons from this episode, we are at risk of engaging in equally ill-founded wars in the future.

And now, 10 years later, we need to ask ourselves how the Australian government was able to ignore the public expression of outrage about its intentions. The key lesson we must learn is to ensure that Australian governments can never again commit our forces on the decision of a leader in the face of opposition from millions of Australian citizens, without even our Parliament being consulted. Democracy shouldn't work like that.

The 10th anniversary of the largest outpouring of anti-war protest this country has ever seen is a fitting occasion for an inquiry into the Iraq war.

The former secretary of the Department of Defence, Paul Barratt, along with former PM Malcolm Fraser, former chief of the Australian Defence Force General Peter Gration and many other distinguished Australians have recently formed a Campaign for an Iraq War Inquiry to facilitate a national conversation about the big questions of how and why the Howard government committed Australian military personnel to invade Iraq in 2003. Their efforts are supported by Senior Australian of the Year, Professor Ian Maddocks.

Britain and the Netherlands have both conducted such inquiries, revealing much that was hidden in those countries' Iraq war decision-making. Of course, the government and opposition will resist, counting on the resignation many felt for the past decade to shield them from public pressure. But the demand for an inquiry into what happened 10 years ago can sow the seeds for a democratic capacity to ensure it never happens again.