BEIJING — FOR one former Beijing policeman, memories of the 1989 Tiananmen Square protests that crescendoed to the brutal military crackdown are still sharp: standing, arms interlocked with other police, staring down student demonstrators, using weapons for the first time, and mounting machine guns on police station roofs out of fear of attack.
''If I were in the position of the government, I would have done the exact same thing,'' says the former officer about the Army's massacre of unarmed students and citizens on June 3 and 4.
Six years after being ordered to turn on their own citizens, China's security forces -- the People's Liberation Army, the paramilitary People's Armed Police (PAP), and the Public Security Bureau or police -- are as troubled and uneasy as the society they are pledged to preserve.
Still, in a moment of reflection, the former cop wonders about the fate of the student leaders and dissidents who fled China in the aftermath, especially Fang Lizhi, the astrophysicist who took refuge in the US Embassy and was later allowed to seek exile in the United States.
''He was so outspoken and brave to tell the truth,'' the 15-year police veteran, who resigned last year, says with admiration.
The police in China today are in a quandary. Official corruption in China has become so pervasive, it has vitiated police relations with communities and darkened the daily lives of many Chinese. Increasingly, press reports claim, the Army is thrust into situations at odds with the police and is often needed to intervene in disputes between civilians and local police.
As the ruling Communists wrestle over succession to ailing leader Deng Xiaoping, the military, paramilitary, and secret police are poised as key powerbrokers in the struggle and divided by loyalties to rival politicians. At the same time, crime is overwhelming cities and rural areas and demoralizing and sweeping police into gambling, prostitution, and drugs.
''The situation is helpless. Corruption is too widespread,'' says a former officer who served 10 years in the Beijing police and now drives a taxi. ''The Public Security Bureau is not very good at cracking crime cases because it's hard to get people to show any initiative.''
''There is lots of scope for friction among the security forces,'' says a Western military official in Beijing. ''The element of trust that should exist between a country and the police seems to be going down steadily in China.''
As the sixth anniversary of the Tiananmen Square unrest approaches Sunday, the Chinese police have again been called on to stifle dissent. A series of petitions urging a more open political system and a reassessment of the 1989 unrest has produced the most sustained pro-democracy drive since then. Several prominent activists across China have been arrested or questioned during the last two weeks.
Those dark days after martial law and the military massacre rent the Army and, analysts believe, led to the court-martial and even execution of several hundred officers, remain extremely sensitive among military officials. Indeed, in the interest of maintaining a united front, leaders are unlikely to reopen such a divisive issue in the near future, analysts say.
What did emerge from the 1989 turmoil was revival of the armed police as the premier security force. Estimated to number 800,000 to 1 million, about the size of the Army, the paramilitary police now get the best recruits, training, and equipment in order to maintain Communist control. ''PAP troops will do their utmost for the nation's stability,'' Armed Police Commander Ba Zhongtan, was quoted as saying by the New China News Agency.
Western analysts say the armed police have also become a key cog in President Jiang Zemin's efforts to consolidate his power as Mr. Deng's health reportedly fails. In recent years, Mr. Jiang has effectively courted the Army and paramilitary police with promotions, frequent visits, pay increases and, for young officers, a strict enforcement of retirement deadlines.
During April and May, Mr. Ba, the armed police commander, oversaw Jiang's antigraft campaign against senior Beijing party leaders and could be promoted to the all-powerful Central Military Commission, also headed by Jiang, in what could be a major military shake-up later this month.
Western analysts say aging veteran generals Liu Huaqing and Zhang Zhen could retire or be nudged aside to make way for Jiang's proteges Chi Haotian and Zhang Wannian in top commission positions.
The leadership shifts could also be a litmus test of Deng's lingering influence. His key military aide, Wang Ruilin, is poised for appointment to the commission but could lose out if Jiang moves aggressively to sideline the corrupt Deng family. Already, He Ping, head of Army procurement and Deng's son-in-law, is reported to be under investigation and could become another antigraft victim, diplomats say.
In an important future decision, party and military leaders are currently debating who will have jurisdiction over the powerful paramilitary. In his battle to win control of the security forces, Jiang also could face challenges from Yang Shangkun, a veteran revolutionary ousted in a 1992 military purge but still influential in the Army, and Qiao Shi, a former secret police chief.
''In any post-Deng succession, the PAP will be crucial,'' says a European analyst. ''Jiang will never have the ... military support like Deng, but the military perceives him as the best bet at the moment.''
Politics aside, the major worry of ordinary Chinese is rampant crime snuffed out after the 1949 communist victory but revived along with economic reforms. Although still limited by Western standards, major crime surged almost 16 percent in 1994, according to government figures.
For Beijing residents, violence clouds daily life. A survey reported in March in Legal Daily newspaper showed that 70 percent of the respondents felt unsafe in the Chinese capital. In a recent incident that would have been unheard of just a few years ago, Chinese sources say, the son of a Chinese ambassador to one of the former Soviet republics murdered an old woman in a neighboring apartment for irritating him by cracking walnuts.
''That's how tense and jittery everybody is,'' says a friend of the victim's family.
Beijing residents and Western analysts say that not all police are corrupt. In March, 30,000 city residents lined the streets for the funeral of Cui Daqing, a respected officer killed while chasing a robber.
But some of his former colleagues, who derisively refer to Cui as ''the hero,'' say he was silly not to think of himself. Although the government has doubled police salaries in the last year, a beginning officer in Beijing makes less than $100 per month and regularly extorts meals, expensive gifts, and apartment units in new government housing.
Former police say that Beijing police officers are often paid to wink at growing crime, and senior officers are involved in gun- and drug-running. ''Trafficking in drugs and weapons can't take place unless a high-level police official is involved,'' says one former cop.
''In China, we have a saying: If you have power, use it or it will expire,'' he says.