The last position of power retained by Hua Guofeng, chairman of the Central Military Commission, was taken by Deng in 1981. However, progress toward military modernization went slowly. An actual border war underway with Vietnam in 1977–79 made major changes unwise. The war puzzled outside observers, but Xiaoming Zhang argues that Deng had multiple goals: stopping Soviet expansion in the region, obtain American support for his four modernizations, and mobilizing China for reform and integration into the world economy. Deng also sought to strengthen his control of the PLA, and demonstrate to the world that China was capable of fighting a real war. Zhang thinks punishment of Vietnam for its invasion of Cambodia was a minor factor. In the event, the Chinese forces did poorly, in terms of equipment, strategy, leadership, and battlefield performance. China's main military threat came from the Soviet Union, which was much more powerful even though it had fewer soldiers, because it was far advanced in all sorts of weapons technology. In March 1981, Deng deemed a military exercise necessary for the PLA, and in September, the North China Military Exercise took place, becoming the largest exercise conducted by the PLA since the founding of the People's Republic. Moreover, Deng initiated the modernization of the PLA and decided that China first had to develop an advanced civilian scientific infrastructure before it could hope to build modern weapons. He therefore concentrated on downsizing the Army, cutting 1 million troops in 1985 (百万大裁军), retiring the elderly and corrupt senior officers and their cronies. He emphasized the recruitment of much better educated young men who would be able to handle the advanced technology when it finally arrived. Instead of patronage and corruption in the officer corps, he imposed strict discipline in all ranks. In 1982 he established a new Commission for Science, Technology, and Industry for National Defense to plan for using technology developed in the civilian sector.