A major power such as China, with its long borders, heavy dependence on maritime trade and painful history of invasion, has every right to maintain a potent defence force. In this context, its desire to build an aircraft carrier makes sense. An argument can readily be made that such vessels are necessary to protect commercial shipping and allow the projection of military force to safeguard other vital national interests. Other military powers including the United States, Russia, Britain, France, Spain, Italy and India have reached the same conclusion. However, it also must be acknowledged that China's carrier programme is certain to give rise to unease in the region. Senior Chinese naval officers writing in a range of military journals have often explained why the country needs these warships, but there have been few official statements. Nevertheless, opinion is firming that China will soon have an aircraft carrier. A Soviet-era carrier bought from the Ukraine 12 years ago appears to have recently left dry dock at a Dalian shipyard with extensive work having been done to its superstructure. A concrete replica of its flight deck is believed to be under construction in Wuhan . Beijing has yet to comment, but some military analysts believe photographs of the carrier and the concrete replica posted on the internet are further evidence that China is close to deploying an operational carrier. Certainly some foreign military experts are convinced, and we assume they have better information. The most senior US military officer in the Asia-Pacific region, Admiral Robert Willard, recently told a US Congressional hearing that the carrier would be operational around 2012 and would most likely be used for training. Western defence community insiders believe a domestically built carrier will go into service after 2015, most likely in 2020. Such observations, coupled with other clear signs of China's growing military firepower, including modern submarines, missiles and strike aircraft, are beginning to reshape military ties in Asia. The repair of an American navy supply ship at Vietnam's Cam Ranh Bay port reported in this newspaper this week was the most recent example. In this case, former foes are moving closer together as a counter to China's growing military might. Short of nuclear weapons, which China already has, there is no more potent symbol of power and prestige than an aircraft carrier. A carrier, its aircraft, support ships, protective submarines and communications and surveillance systems are expensive and sophisticated. Complex training and co-ordination are required to make use of these warships within a coherent military doctrine. A carrier announces to the world that a nation is capable of marrying technical complexity with military organisation to deliver intimidating firepower far from home. But embarking on such a course is certainly expensive, and potentially destabilising for the region. No countries are fully transparent about their defence planning, but if China is determined to operate carriers the government should make more effort to explain its thinking. It would help if Beijing published a comprehensive defence white paper or rationale showing where a carrier fits into the nation's overall defence posture. Adequate reasoning has to be given to taxpaying citizens as to why hundreds of billions of yuan should be spent this way rather than on improving health care, education and other essential public services that are severely underfunded. In this, as in so many other areas of national policy, there is too little explanation or public debate.