Malaysia's Prime Minister Najib Razak meets China's President Xi Jinping at the Diaoyutai State Guesthouse in Beijing on November 3, 2016. (Jason Lee/AFP/Getty Images)

IN RECENT months, countries from the Maldives to Monte­negro have discovered the dark side of China’s Belt and Road Initiative, a multitrillion-dollar plan to finance infrastructure in 70-odd countries. Ports, railroads and other projects are being built with funds borrowed from Beijing, and governments are discovering that the crippling debt has become an economic and a political trap. Why would they get themselves in such a mess? The answer, in at least a few cases, is corruption.

A jaw-dropping article in the Wall Street Journal this week offered a dramatic example. According to documents reviewed by the newspaper’s reporters, senior Chinese officials offered to help Malaysia’s then-prime minister escape from a financial scandal in exchange for signing on to huge railway and pipeline projects that would be built at inflated prices by Chinese state companies, with money borrowed from Chinese banks. Previously, Journal reporters had helped to expose how hundreds of millions of dollars from a Malaysian state investment fund had flowed into the bank account of then-Prime Minister Najib Razak; investigations by prosecutors in the United States and Switzerland followed.

The new Journal report says that, in a series of meetings in 2016, Malaysian officials agreed to bail out the development fund by contracting to spend $16 billion on a rail line, or more than twice its projected cost, and another $2.5 billion on a gas pipeline. Senior Chinese officials, who said they were acting on instructions of President Xi Jinping, offered an extraordinary sweetener: They said they were conducting “full operational surveillance” of the Journal’s Hong Kong bureau and its staff, and would hand over “a wealth of data to Malaysia through ‘back channels,’ ” according to Malaysian notes seen by Journal reporters. The Chinese promised to help Mr. Najib identify the Malaysian sources who had reported on the graft and to use their influence to stop the investigations in the United States and elsewhere.

The plan badly backfired. Mr. Najib signed the contracts but then lost an election in May to an opposition coalition. A new government promptly opened its own criminal investigation and brought criminal charges against Mr. Najib, who denies wrongdoing. The current prime minister, Mahathir Mohamad, suspended the Chinese projects while on a visit to Beijing, bluntly telling his hosts that “we do not want . . . a new version of co­lo­ni­al­ism.”

The rebuff won’t stop China’s attempts to turn Malaysia into a client state; it is still building a huge port on the strategic strait of Malacca that could someday accommodate its aircraft carriers. But the story of how it allegedly suborned the Malaysian government will be read closely by people in other countries wondering about the huge and non-transparent deals their governments are making with Beijing. As it should be.