Trump says China will curtail fentanyl. The U.S. has heard that before

The United States has long pushed China to systemically control all fentanyl substances
The New York Times (US)
Monday, December 3, 2018

China vows to stem the supply of the powerful opioid fentanyl flowing into the United States. It pledges to target exports of fentanyl-related substances bound for the United States that are prohibited there, while sharing information with American law-enforcement authorities. Such promises, echoed in the recent meeting between the countries’ presidents, ring familiar. Cracking down on the manufacturing and distribution of fentanyl in China is no easy task. Many classes of the drug are already considered controlled substances in the country. Fentanyl’s chemical structure and those of related analogues can be modified to create similar yet distinct substances, so new versions can be concocted quickly.