NOTHING would be more certain to mar Hong Kong's forthcoming reunification with the mainland than military action against Taiwan in the run-up to the handover. The effect on public and investor confidence would be tremendous. The stock market would plummet, emigration accelerate and trust in the 'one country, two systems' concept evaporate. President Jiang Zemin seems to recognise this. That is why his recent speech to the Preparatory Committee was careful to stress the Taiwan issue must wait until the re-integration of Hong Kong and Macau has been successfully completed. Now he has privately cautioned the People's Liberation Army's (PLA's) senior generals that their desire to invade Taiwan could wreck the Hong Kong economy and kill all hope of a smooth transition. Unfortunately, it is far from clear this warning will be heeded. While Mr Jiang may have initially encouraged last summer's sabre-rattling against Taipei, in an effort to secure PLA backing in the struggle to succeed Deng Xiaoping, events since seem to have spiralled out of his control. One missile test was conducted without prior Politburo approval, and the party has been unable to exercise anything more than nominal supervision over the preparations for further exercises, now underway in the so-called Nanjing War Zone. So, even if he wishes to, Mr Jiang may find it difficult to check the drift towards further hostilities, despite being chairman of the supposedly all-powerful Central Military Commission. This apparent lack of political control over the PLA leadership has far-reaching ramifications, stretching beyond the present dispute. While a full-scale invasion could never be launched without Politburo Standing Committee approval, it would be easy for trigger-happy generals to manufacture a major confrontation out of some minor mishap, perhaps involving stray mainland fishermen. Worse still is the possibility of freelance military action in other areas. If the party is unable to control the PLA over Taiwan, there is little reason to expect it can rein in the future Hong Kong garrison, or ensure they obey the promises China's political leaders have made regarding the territory's future. It is rare that it is in Hong Kong's interests to see the Politburo exercise tighter control. But this is an exception to the rule. Hostilities across the strait would be a national disaster. Not only Hong Kong and Taiwan would suffer, but also the entire nation. If the military cannot recognise this, it must be hoped their political counterparts do, and can still exercise enough control to stop the PLA leading China down the road to war.