On New Year’s Day, Cambodian Prime Minister Hun Sen launched a six-month crackdown on the drug scourge that he said had become an increasing grievance for the country’s people.

His announcement came shortly after a state visit by Philippine President Rodrigo Duterte, who in 2016 launched a violent anti-drugs campaign in his own country that went on to kill 7,000 people in seven months.

Given that Duterte’s crackdown was suspended after rogue police officers kidnapped and killed a South Korean businessman, it is perhaps not surprising that Hun Sen, after the first spike in detentions in February, rushed to assure Cambodians that his campaign would not be bloody.

And, sure enough, while Duterte’s crackdown made headlines the world over, Hun Sen’s has escaped such scrutiny. Yet while it is true that Cambodia’s crackdown has avoided the kind of violence associated with Duterte’s campaign, that has not allayed fears of serious abuses.

Such crackdowns are only one aspect of the region’s struggle against drugs – ministers and delegates from six Mekong countries (Cambodia, China, Laos, Vietnam, Myanmar and Thailand) agreed a regional drug policy with representatives from the UN Office on Drugs and Crime last Wednesday – but they are its most visible.

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Phil Robertson, deputy director of Human Rights Watch’s Asia division, said that while Duterte had unleashed police and vigilantes to shoot thousands of small-scale drug dealers or users on the streets, Cambodian authorities were arresting more drug users and shoving them into woefully overcrowded prisons.

“It’s the difference between sudden human rights abuses, and gradual but deadly rights abuses,” said Robertson. “In Cambodia, it’s only the families and the lawyers who see how bad the prison conditions are for the thousands of people in pretrial detention.”

Even before Hun Sen’s crackdown, Cambodia had been criticised for the conditions in its prisons – for practices such as the involuntary detention of drug users in “rehabilitation centres” and because many people serve entire prison sentences before their cases have even reached trial.

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Such delays mean the prison population is heaving. As of December, before the crackdown started, 8,902 of the 22,000 people in prison were being held for drug offences.

Robertson said Hun Sen’s campaign was having an alarming side effect, as it had driven drug use further underground, encouraging addicts to hide and reuse needles, putting them at greater risk of HIV. But, again, he says, “that’s not seen by many or particularly well known”.

Sithat Sem, drug programme manager in Phnom Penh for the NGO Friends International, a Cambodia-based social enterprise, said users were still accessing services, but requesting fewer syringes so as not to draw police attention. Drug users had also begun to divide into smaller groups or live alone, hiding in their community or moving to other places, he said.

“All this means we have more constraints on finding them and reaching them with our services”, he said. “We are concerned about the impact this will have on targets for HIV elimination in 2025 and 90-90-90 Targets in 2020, which the national government along with UN has committed to.”

Under the “90-90-90” initiative, by 2020, 90 per cent of people living with HIV will know their HIV status; 90 per cent of people diagnosed with HIV will get continuous antiretroviral therapy; and 90 per cent of people receiving antiretroviral therapy have viral suppression.

The prevalence of Aids among Cambodians who inject drugs is 25 per cent. The needle and syringe programme, HIV testing and education are among the most important approaches to preventing new cases among this at-risk group.

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Cambodian officials said the government’s crackdown was a response to a nearly 30 per cent increase in the number of documented addicts to 2016. But critics attacked this as pre-election propaganda: communal elections are scheduled for June, to coincide with the end of the anti-drug campaign.

For some critics, Hun Sen’s crusade is intended as a distraction from increasing political repression. In February the prime minister’s long-time opponent Sam Rainsy was forced to abandon the leadership of the Cambodian National Rescue Party in the face of a threat of a ban against any political party whose leader is convicted of a crime.

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Sam Rainsy had been convicted on a series of defamation charges, and has lived in France since 2015 to avoid punishment.

According to David Harding, an independent drug expert with a decade of experience in Cambodia, the focus of the war on drugs has been on both demand and supply, but, he said, “there is little evidence to show that there has been an impact on traffic or cultivation”.

Mass arrests, he said, just transferred the issue of drug use from the community to the penal system, which he said was already overstretched, and served no long- or even medium-term purpose except for moving the problem out of sight and appearing to be doing “something”, for populist political gain.