LAST month a combined force from five allied nations, including a fleet of 33 warships and submarines, over 200 aircraft and more than 33,000 military personnel, defeated an ‘enemy force’ in 20 locations across northern Australia. The enemy, of course, was an imaginary one and the battle was a military exercise, Talisman Sabre 17, but its successful conclusion raises some interesting questions about future co-operation between the US, Australia and New Zealand.