Despite being Cambodia’s principal ally and benefactor at the time, China’s influence over Democratic Kampuchea between 1975 and 1979 was surprisingly weak, a new academic study has found.

Drawing on interviews with former Khmer Rouge cadres, previously uncited primary sources and testimony from the ongoing trial of former leaders, the paper presents a China that tiptoed around the smaller ally.

“The xenophobic DK leadership defended its autonomy fiercely and China trod gingerly, even when brutal and reckless [DK] policies jeopardised Democratic Kampuchea’s viability, embarrassed China abroad and invited war with Vietnam,” the article says.

Written by Asian foreign policy scholar John Ciorciari and published in the journal Cold War History in May, China and the Pol Pot Regime also draws links between DK-era policies and contemporary Chinese foreign policy.

“The same fear of a weak state’s failure informs contemporary Chinese policy towards North Korea and lessens Beijing’s ability to drive reform in that country,” Cior-ciari writes.

According to the paper, although China and Democratic Kampuchea shared Maoist ideological roots, their partnership was one of “mutual suspicion” and based more on strategy than “ideational affinity”.

In short, DK needed the extensive aid the Chinese were willing to offer, while the PRC saw Cambodia as an “important hedge” against an increasingly hostile Vietnam.

Though thousands of low-level Chinese officials and advisers were deployed throughout the country, the paper states that it was unclear whether they directly witnessed killings.

Even when reports of the executions began to surface, the Chinese failed to moderate domestic policy and instead increased aid, the paper says.

In perhaps the fiercest admonishment from the PRC, Chinese premier Zhou Enlai was said to have warned regime leaders from his deathbed that their recklessness could bring “catastrophe upon the people.”

“Chinese actions revealed that Beijing’s priority was to keep its troublesome ally from collapse – an approach that turned Democratic Kampuchea’s weakness into a source of leverage,” Ciorciari writes.

Speaking at his trial hearing last year, former Khmer Rouge chief ideologist Nuon Chea explained the unconditional nature of Chinese aid.

“There was no political assistance, there was only technical assistance . . . [It] was provided without any condition” he said.

As Cambodia drifted further towards war with Vietnam, in 1978, 100,000 cadres were purged in a six-month period, with alleged internal Chinese documents said to reveal that China “sanctioned the purges”.

With China’s current role as a key Cambodian investor and benefactor, leaders have tried to play down these historical links, the paper says.

However, Youk Chhang, director of the Documentation Center of Cambodia, which provided a number of documents that were used by Cior-ciari, said such studies help both parties.

“China was the biggest supporter of the Khmer Rouge. It’s no secret,” he said. “But, when it comes to scholarship, we need to analyse how strong the influence was.”