MANN: Yeah, it's pretty remarkable. When I first started reporting on fentanyl, A, most experts said stopping this drug or even slow [inaudible] significantly would be nearly impossible. That's because fentanyl is just easy to make from industrial chemicals. So drug policy experts I've been speaking to think Biden expanded health care and drug addiction treatment programs in ways that saved lives. And this new paper suggests Biden's team also convinced China to help curb the sale of so-called precursor chemicals that are needed to make fentanyl in ways that really hit the drug gangs hard. Again, here's Keith Humphreys.