As expected, the 15th anniversary of the June 4 crackdown on Friday has passed without major incident. University campuses and Tiananmen Square in Beijing were blanketed with calm and silence - amid tight security - despite the depth of tension and anxiety beneath the surface. In Hong Kong, tens of thousands of people turned Victoria Park into a sea of flickering lights as they commemorated the deaths of people in the heart of Beijing 15 years ago. In major cities overseas, former student leaders reunited to remember the deaths and express fresh hopes for a free and democratic China. Speaking during a tour of Europe, Politburo Standing Committee member Wu Bangguo reiterated that the party had dealt correctly with the political incident. Stability and unity, he said, were above everything for the nation. To the ruling party, the phenomenal growth of the economy in the past 15 years is solid evidence they took the right decision in ordering troops to suppress the student-led protest. Hu Jinbao and Wen Jiabao, successors of the third-generation of leaders who took over less than two years ago, had hoped that the stability and momentum of development would not be disrupted by incidents such as a fresh dispute over the handling of June 4. That said, there is no doubt the June 4 crackdown has remained an unwelcome source of disquiet and anxiety inside and outside the ruling party. At this time each year, the state security organs are on high alert for any commemorative activities. Prominent government critics have conspicuously disappeared, only to resurface after June 4. This year, senior-ranking cadres have been asked to watch a 210-minute video on the Tiananmen protests produced by the party's propaganda department aimed at unifying their thoughts. One school of analysis was that the move, initiated by former premier Li Peng, was aimed at emphasising all major decisions in the summer of 1989 were collectively made by the leadership then. Any attempts to revisit June 4 to finger individual leaders would therefore destabilise the party leadership. Another school of thinking is that revisiting the decision-making process can clarify who made what decision, thus paving the way in the long run for naming some leaders who should be held responsible for the crackdown. However contrasting the analysis, there is one clear and simple observation, and that is that as long as the leaders of the June 4 era remain alive, with influence in the party, the possibility of a reversal of the official verdict is slim. Ding Zilin, who champions the Tiananmen Mothers advocacy group, has recently quoted public security officials as saying 'it is not possible to resolve the problem of June 4 under the present leadership'. Like it or not, any full-scale investigation and review of the official handling of June 4 will have to be left to the next generations. From the outset, it appears there has been no powerful force within the party and on the mainland applying pressure for a change in the June 4 verdict. As the economy and living standards continue to improve, more people will take an understanding attitude towards the Tiananmen decision. That does not mean the collective memory of June 4 will fade into history. Public aspirations for the whole truth of Tiananmen to be told are unlikely to wane as time goes by. Within the ruling party, June 4 will remain an inglorious chapter in its history. It is hardly surprising that many are adamant wounds left in the hearts and minds of people need to be healed sooner or later. And ironically, the faster the pace of economic growth and social progress of the nation, the greater the pressure on and from within the party for the verdict of June 4 to be corrected. To borrow the wisdom of Mao Zedong, history cannot be changed by the subjective will of individuals.