BEIJING – Should Beijing crack down harder on fentanyl – a synthetic opioid whose abuse results in thousands of American deaths a year – in exchange for Washington easing the trade war?

US President Donald Trump has pushed this demand since February, putting the issue of US-China anti-drug cooperation back under the spotlight alongside both countries’ tit-for-tat tariffs dispute.

The US has alleged that Chinese chemical companies produce the vast majority of the key ingredients, known as precursors, used to make fentanyl that is trafficked by cartels in Mexico across the border into the US.

“If fentanyl ends, I think these (tariffs) will come off,” US Commerce Secretary Howard Lutnick said in an interview on March 9, before China’s latest retaliatory tariffs kicked in on March 10.

While observers say China could do more to prosecute errant Chinese sellers of ingredients used to make fentanyl, Beijing sees little incentive to cooperate with the country it feels is the greatest threat to its development.

The US says China should be doing a lot more about fentanyl control, while China insists it has done more than enough. And the upshot of this stalemate is that the current trade war may persist for a while yet.

Fentanyl has been identified as the leading cause of death for Americans aged 18 to 45. It is used medically as a painkiller, but is highly addictive and potent, even in tiny amounts, and can be easily concealed.

China has traditionally taken a strong anti-drug stance, both domestically and in international forums. Since Mr Trump’s tariff threat, its officials have consistently said the “root problem” of the fentanyl crisis lies with the US.

On March 12, officials from China’s foreign and public security ministries told reporters that the country has done all it can for the US, and Washington should have said a “big thank you” instead of imposing tariffs on China.

On March 4, following Beijing’s announcement of retaliatory tariffs against US goods, China’s Cabinet issued a White Paper outlining its efforts at controlling fentanyl, including how it has launched campaigns against the illegal manufacturing and trafficking of fentanyl-related substances.

Associate Professor Chong Ja Ian, who researches US-China relations at the National University of Singapore, sees the White Paper as a response to charges by the Trump administration that Chinese efforts to stem the flow of fentanyl into the...