rewrite this title Opinion | The Hidden Cost of Trump’s Trade War on China

When President Trump placed new tariffs on China this month, he doubled down on one of his top demands on Beijing: to rein in the chemical companies fueling the illicit production and trafficking of fentanyl into the United States. Mr. Trump has long argued that China is a huge contributor to overdoses that have killed more than 400,000 Americans over the last decade, and he’s right. For years, Chinese companies have supplied the vast majority of the lethal chemicals that drug cartels around the world use to produce the fentanyl flooding American streets.

But starting a trade war isn’t a solution to this problem — and could make it worse. Tariffs alone will not push China’s government to help reduce drug overdose deaths in the United States. In fact, with Beijing already imposing retaliatory tariffs and proclaiming that it’s “ready to fight till the end,” Trump’s blunt-force tactics might drive China to cooperate less on fentanyl, not more. With the stakes as high as they are, American communities cannot afford a miscalculation.

Starting in 2016, overdose deaths from synthetic opioids — primarily fentanyl — began skyrocketing across the United States. When Joe Biden took office in early 2021, the number of such deaths had increased 30 percent from the previous year, with tens of thousands of Americans killed. In February 2024, my family joined the hundreds of thousands of American families who have lost a loved one to this epidemic when a relative died from a fentanyl overdose. This personal tragedy happened just two weeks after I joined the State Department to help lead the Biden administration’s effort to address global fentanyl trafficking.

With heightened clarity about fentanyl’s devastating impact, I spent the past year helping lead the U.S. diplomatic offensive to curtail Chinese companies’ role as the global suppliers of the precursor chemicals that are used to make illegal fentanyl. We used every lever of American power — from law enforcement to sanctions to diplomacy — to pursue progress on curbing fentanyl precursors with China’s government. And while it wasn’t perfect, it was working.

In 2021, President Biden issued an executive order imposing sanctions on individuals and companies engaged in the illicit opioid trade. His Treasury Department put sanctions on more than 300 individuals and entities, freezing entire networks of fentanyl suppliers and traffickers out of the international financial system. In 2023 and 2024, Mr. Biden identified China as a major illicit drug-producing country for its role in the synthetic opioid trade, a blow to the reputation of China’s chemical industry.

Simultaneously, the Biden administration pushed U.S. law enforcement agencies to conduct aggressive investigations and build indictments against dozens of Chinese citizens and companies that were trafficking fentanyl precursor chemicals into the United States. The Department of Justice worked closely with foreign governments from Fiji to Morocco to arrest Chinese traffickers and extradite them to the United States for prosecution. The first convictions were handed down just last month.

The Biden administration matched these accountability measures with diplomatic action. In July 2023, Secretary of State Antony Blinken started the Global Coalition to Address Synthetic Drug Threats, rallying more than 160 countries — not including China — to step up efforts to combat the synthetic drug trade, effectively aligning the world with Washington’s agenda, not Beijing’s.

This initiative set the stage for President Biden to secure a personal commitment from President Xi Jinping to restart counternarcotics cooperation in November 2023 — an essential step in China’s hierarchical, authoritarian political system, where decisions about how and when to cooperate with the United States are controlled at the very top. In parallel, China’s government issued a public notice to its chemical industry that detailed criminal punishments for selling precursor chemicals that could be used to produce illicit fentanyl and other narcotics.

Throughout 2024, between multiple cabinet-level meetings and repeated rounds of technical talks, the Biden administration continued to push China to impose new restrictions on the sale of lethal chemicals and move against criminal traffickers. During that time, Beijing placed new prohibitions on the sale of more than 50 narcotics and lethal chemicals, and joined the United States in voting for new international regulations on fentanyl precursor chemicals at the United Nations.

The United States pressed China to take the first joint law enforcement action against drug trafficking in several years, including the arrest of a key Chinese trafficker. And China’s authorities began much-needed, albeit piecemeal, efforts to take down the online marketplaces that sell lethal chemicals to international drug trafficking syndicates.

Can China’s government do more? Absolutely. It can get serious about curbing the underground banking and financial crimes that facilitate sales of precursor chemicals. But in combining diplomacy with concrete actions, the Biden administration set the agenda for how the two countries can crack down on illicit fentanyl production.

And we made progress. International fentanyl supply chains showed signs of disruption, forcing traffickers to change sources and tactics. Together with other diplomatic initiatives and an expansive public health campaign, the number of lethal fentanyl overdoses in the United States has dropped. In the 12 months ending September 2024, overdose deaths were down an estimated 24 percent from the year prior. Thousands of American lives have been saved.

The opioid overdose epidemic is far from over. President Trump now has an opportunity to try to finish the job. But to do that, he will need to secure a commitment from Mr. Xi to continue the work that is already underway. Mr. Trump can push China to enforce existing restrictions on its chemical industry more aggressively. He can insist that China fully dismantle the online marketplaces selling fentanyl precursor chemicals to transnational criminal organizations. And he can call for China to place new restrictions on its shipping industry, so that lethal chemicals never leave its shores.

None of this will happen with tariffs alone. Pressuring the Chinese government is an important part of U.S. diplomacy, and tariffs, if deployed skillfully, can provide leverage over Beijing as it attempts to manage its struggling economy. But ramping up pressure without a clear diplomatic or legal road map could reverse recent gains. Chinese officials have already signaled that the new U.S. tariffs “will deal a heavy blow to counternarcotics dialogue and cooperation.”

To make further progress, Mr. Trump will have to direct his cabinet to get to work and engage in the painstaking diplomacy that will be necessary to save more U.S. lives. Regardless of political affiliation, all Americans should hope he succeeds.

Brandon P. Yoder was a deputy assistant secretary for international narcotics and law enforcement affairs in the Biden administration and a Democratic staff member for the Senate Foreign Relations Committee.

The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.

Follow the New York Times Opinion section on Facebook, Instagram, TikTok, Bluesky, WhatsApp and Threads.