Now to say, never again

Under this framework of international law, the use of force is prohibited. The charter says that all nations ''shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state''. This cardinal principle is subject to two exceptions. Nations may go to war where this is authorised by the UN Security Council or where it is an act of self-defence.

The effect is that the use of force by Australia raises different issues than were imagined in 1901. A key question in going to war in Iraq in March 2003 was whether Australia breached its international obligations, which I believe that it did. This had ramifications for the nation and its long-term security and economic prosperity beyond the decision to use force in Iraq. This is one reason why it is no longer appropriate for the decision to go to war to be left solely in the hands of the government. This was especially the case with Iraq where popular opinion was against the war and there were serious doubts about a pre-emptive strike.

Australia went to war in Iraq only after parliamentary debate, although that debate was not binding and occurred only after troops had been pre-deployed. The matter was brought before the House of Representatives in March 2003 on a motion by the then prime minister John Howard. He recognised that the decision lay with his government, but thought it appropriate that the Parliament, at the first opportunity, had the chance to debate this motion. It was considered essential ''that the reason for that decision be made plain to the representatives of the people and that they have a full opportunity to debate them and to have their views recorded''.

The House of Representatives voted on party lines to authorise the use of force. On the other hand, a separate vote in the Senate called ''for the Australian troops to be withdrawn and returned home''. The government ignored the vote in the Senate.

Proposals have sought to make parliamentary votes binding to remove the exclusive power of the government to go to war. As no referendum is needed, it is possible to limit the government's war power by ordinary legislation.

One such attempt was a Bill introduced by Democrats senators Andrew Bartlett and Natasha Stott Despoja soon after the Iraq War began. It sought to give both houses of Federal Parliament a separate veto power over any decision to send Australian troops overseas. The veto would only have been subject to exceptions covering the movement of personnel in the normal course of their peacetime activities and swift action in the event of an emergency. The Bill was not passed and never became law.

A role should be established for Parliament in decisions to use force outside of Australian territory. However, I do not think the Democrats' Bill achieved the right balance. The Senate should not have a separate veto. I favour a compromise whereby the decision to go to war is made by a joint sitting of both houses. This would emphasise its importance and would involve all of the people's representatives in a single vote.

This proposal would generally allow the government to gain the outcome it wishes, with its greater majority in the lower house likely offsetting its deficit in the Senate. While the prime minister's war power would be subjected to new checks and balances and greater deliberation, this would in most cases still enable the government to determine the course for which it will ultimately have to answer at the ballot box.

Lessons need to be learnt from how Australia became involved in the Iraq conflict. Rather than the events of 2003 being forgotten, we should change how we go to war. Any future decision by Australia to take hostile action overseas should also be made by the Federal Parliament.