As part of a crackdown on the importation of synthetic opioids to the U.S from China, nine people were convicted in China on charges of trafficking fentanyl as part of a joint effort by Chinese and American law enforcement agencies. The public sentencing display and harsh sentences, including a death penalty and two life sentences, are what experts believe is China’s way of signaling to Washington that they are committed to combatting drug trafficking.

Fentanyl use has killed thousands in the U.S. About 28,000 people died from overdoses involving synthetic opioids other than methadone, including fentanyl, in 2017.

And overdose deaths specifically involving fentanyl doubled every year from 2013 to 2016. A congressional commission has referred to China as the “largest source of illicit fentanyl and fentanyl-like substances in the United States.” According to U.S. law enforcement and drug investigators China is the “main supplier” of the drug to the U.S., Mexico and Canada.

The U.S. has been asking China to crack down on its fentanyl problem for years now — and made such requests even towards the end of the Obama Administration. China has made a series of commitments indicating they will do so but the problem has persisted.

“Publicizing this is an attempt to send a message that ‘Hey, we’re really serious about this and we’re making moves to crack down,’” Regina LaBelle, who was chief of staff in the Office of National Drug Control Policy during the Obama Administration, tells TIME. American officials have long blamed China for the influx of fentanyl and similar substances reaching U.S. borders. LaBelle recalls several “high-level” discussions with China in which they made commitments in the last year of the Obama Administration to crack down on fentanyl. “They would, in official statements, say the right words,” LaBelle says.

However many believe that China’s lack of oversight over its massive pharmaceutical and chemical industry still poses a daunting challenge for any efforts to crackdown on the production and export of illegal drugs. LaBelle remains skeptical about how much has changed. Asked whether China did enough during President Barack Obama’s tenure, LaBelle responded, “They probably could have moved a little faster because we’re almost in the same place we were.”

Without being privy to classified information, it’s “really hard to tell” whether China is doing enough to stop the illicit flow of synthetic opioids, LaBelle says. She adds that it’s an “extreme challenge,” given the lack of regulation in China’s sprawling chemical industry.

Fentanyl has devastated the U.S. in recent years. The substance is 50 times stronger than heroin, and proving increasingly popular with American drug users. While the rate of overdose deaths from heroin has plateaued in recent years, the rate of overdose deaths related to synthetic opioids, including fentanyl, has been increasing — 45% between 2016 and 2017 (from 6.2 to 9 deaths per 100,000 people).

Fentanyl seizures by U.S. Customs and Border Protection have shot up dramatically in recent years, too. In FY 2013, CBP seized about 1 kg of fentanyl. By FY 2018, the agency seized almost a thousand times that amount. Much of the drug has come through the mail, prompting Trump to order the U.S. Postal Service and express shipping companies to “SEARCH FOR & REFUSE all deliveries of fentanyl” earlier this year.

President Trump has previously said that Chinese President Xi Jinping had told him that China did not have a drug problem, because it could (and does) use the death penalty to punish drug dealers. However, data and experts point to an increase in drug users in the country, suggesting China does have problems with drug abuse.

A top Chinese drug official denied allegations by Trump that China is the reason for most of the supply of America’s fentanyl just two months ago. A congressional commission previously stated that China does not have a domestic fentanyl abuse problem and this is the reason its production is not prevented. “Because illicit fentanyl is not widely used in China, authorities place little emphasis on controlling its production and export,” notes a 2017 report from the U.S.-China Economic and Security Review Commission.

Thursday’s sentencing appeared to be a victory for the White House. Jim Carroll, policy director for the Office of National Drug Control, said in a statement issued on the same day that “the concrete action taken by China is a direct result of President Trump’s strong leadership on this issue, and the personal engagement by many members of Congress.”

As part of a wide-ranging deal between Trump and Chinese leader Xi Jinping last December, China had reportedly pledged to designate fentanyl and similar drugs as controlled substances, subjecting those who sell them to harsh punishments and potentially slowing their flow into the U.S. In April, China announced that it would follow through on its pledge to control all fentanyl-related substances as a class and did so the following month.

The rare collaboration between the two countries comes in the midst of an ongoing trade war that has lasted for more than a year and strained American and Chinese economies. On Friday, Trump pushed back on comments from a Chinese official that the U.S. would roll back the higher tariffs slapped on Chinese goods, the Associated Press reported.

China’s decision to very publicly convict the fentanyl traffickers at this time appears to be an attempt at political posturing and gaining “leverage” in ongoing trade talks for some experts. Bryce Pardo, an associate policy researcher at the RAND corporation who has worked with the national government on drug policy, points out that it’s important to note that some of the arrests in the case may have been made two years ago. The timing is “more than just a coincidence,” he says and likely is a message from China that “they’re doing something.”

The public sentencing does, however, highlight successful cooperation between the two countries at an otherwise tense time. Pardo notes that the convictions show the results of “a very positive collaboration effort” and that such intelligence and information sharing is key to tracking down individuals involved in manufacturing synthetic opioids.

Even if China was to successfully get the production and export of fentanyl under control, it would not necessarily mean the end of fentanyl being imported to the U.S. China is “just one piece of this puzzle,” Pardo says. “At the end of the day, fentanyl manufacturing will not stop,” even if “China does get its regulatory house in order.” India also has a massive pharmaceutical industry with little regulation and just last year, Indian authorities reported two relatively large seizures of fentanyl apparently headed for North America.

While China grapples with its supply crisis, it’s imperative for the U.S. to focus on curbing demand and enacting effective harm reduction measures to minimize and prevent overdose deaths, LaBelle says. “We have to recognize both sides of this equation,” LaBelle says. “Without customers, there wouldn’t be a market.”

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Write to Sanya Mansoor at sanya.mansoor@time.com.