Jeffrey Singer

Trump's executive order describes street fentanyl as a chemical weapon, but many drug policy experts say fentanyl would be difficult to use as a weapon, and it's never happened before in the U.S.

Jeffrey Singer is a physician and an expert on addiction at the Cato Institute.

Trump had already classified drug cartels as terrorist organizations and launched military strikes against alleged drug boats.

Deaths from street fentanyl were already declining in the U.S.

before Trump militarized the response, dropping 27 percent last year, according to federal data.

Brian Mann, NPR News.