WHEN THE CHINESE leadership was forced to admit it had covered up the extent of the infectious disease called severe acute respiratory syndrome, or SARS, it responded with what many called the most serious political shake-up since the Tiananmen Square massacre of 1989. The government sacked the minister of health and the mayor of Beijing from their government and party posts, admitted that the number of patients and deaths in the capital was radically higher than previously disclosed--in other words that it had lied--and launched a mass propaganda campaign to deal with the illness.

If these dramatic moves were intended to distract attention from months of deception and negligence, they succeeded. Senate majority leader Bill Frist, visiting Beijing with a congressional delegation, offered President Hu Jintao "tremendous compliments because he took bold action over the last 48 hours while we were here in China to boldly and courageously address this virus." With all due respect to Dr. Frist, there are exemplars of courage in the SARS fiasco, but Hu is not among them.

Understandably, however, the unusual firings and rapid about-face have fed hopes that China has turned a political corner. "This is the beginning of the end," a senior Chinese official credited with democratic sympathies told the Washington Post's John Pomfret. "This is the spark many of us have been waiting for."

If China's policy reversal in its handling of SARS is a political watershed that signals greater openness and accountability, then we need to know what brought it about.

There are two answers. First, international pressure became too intense to ignore. Once the disease spread abroad, via Hong Kong, China's callous neglect of its people's health was no longer only its affair. Foreign governments coping with SARS were furious. Even Hong Kong's favored elite, always quick to take Beijing's side, felt betrayed. China's response to the disease was embarrassing by comparison with that of Taiwan, which sought to cooperate with the World Health Organization even though it is denied membership by the international "One China" policy. Prominent visitors like British prime minister Tony Blair postponed visits. The Rolling Stones cancelled concerts. Business and tourist travel fell off. Even the WHO--which had publicly praised China for its cooperation, while itself being barred from the site of the outbreak in Guangdong province--privately welcomed press scrutiny and external pressure on the regime. Ultimately, the WHO told China, "The international community doesn't trust your figures."

This skepticism arose from the second factor behind the regime's abrupt reversal: truth-telling from inside China. A lone retired military doctor--Jiang Yanyong--contacted the media to say that Beijing was lying about the number of cases in the capital. Personnel from other hospitals followed his example, telling reporters that they had been told to hide patients suffering from SARS in a hotel and in ambulances that were driven around the city while WHO investigators conducted visits.