THE LEADERS of China talk about corruption as if it were merely a failure of party discipline. The new general secretary of the Chinese Communist Party, Xi Jinping, became the latest to suggest this in a speech delivered just after his rise to the top post on Nov. 17. “We must be vigilant,” Mr. Xi declared, warning that corruption threatens to corrode both the party and state.

He’s right about the threat. Corruption is rife in Chinese government, business and society, blossoming along with China’s remarkable economic growth. But Mr. Xi’s admonition will do nothing to stop corruption, and the reasons are not hard to find. China possesses a semblance of a legal system, with courts, lawyers and trials. But it has yet to create a genuine rule of law. The definition of rule of law is that no one — not even the party’s elite — is above the law. Yet in China today, the party stands beyond. It often uses the law to punish those who challenge its monopoly on power.

Two recent examples illuminate the party’s exalted position. The first was the downfall of Chongqing party chieftain Bo Xilai, a rising figure in the elite until it was revealed that his wife was involved in a murder scandal surrounding the death of a British businessman. Mr. Bo’s abuses shocked many Chinese when they were revealed, and served to underscore how the system works, enriching and protecting those in power. Mr. Bo lost his footing, but he was the exception rather than the rule. Mr. Xi seemed to acknowledge this in his speech, saying, “In recent years, there have been grave violations of disciplinary rules and laws within the party that have been extremely malign in nature and utterly destructive politically, shocking people to the core.”

The second example was the disclosure by the New York Times that relatives of Premier Wen Jiabao had amassed a multibillion-dollar fortune in businesses, despite Mr. Wen’s own speeches imploring family members of party officials not to exploit their connections.

In a real democracy, an unfettered free press can expose wrongdoing. While muckraking journalism can be found in China today, often it has been sanctioned by the authorities to manage popular anger over a scandal, such as milk contamination or factory pollution. There are red lines beyond which journalists cannot cross, and this includes holding the highest officials to account. When the story broke about Mr. Wen’s family fortunes, Chinese authorities promptly censored it on the Internet. It seems there is a limit to the slogan “We must be vigilant.”

It’s one thing to take a poor, faltering socialist experiment such as Mao’s China and transform it in a single generation into a mega-engine of capitalism. This much has been done, and with great gusto. But the lack of rule of law is a deep flaw that weakens the pillars of China’s progress. As long as this is the case, Mr. Xi’s warnings about corruption will echo in an empty hall.