In May 2015, the White House appointed Chuck Rosenberg to replace Michele Leonhart as the DEA's Administrator. Since it's an interim position, he didn't have to be confirmed by the Senate and has remained so far in the Trump adminstration.
Prior to this appointment, Rosenberg was Chief of Staff to since-fired FBI Director James Comey for 18 months. Before that he was the U.S. Attorney for the Eastern District of Virginia and for the Southern District of Texas dating back to 2006.
On Nov. 4, 2015, Rosenberg told reporters:
'What really bothers me is the notion that marijuana is also medicinal – because it's not. We can have an intellectually honest debate about whether we should legalize something that is bad and dangerous, but don't call it medicine – that is a joke. There are pieces of marijuana – extracts or constituents or component parts – that have great promise. But if you talk about smoking the leaf of marijuana – which is what people are talking about when they talk about medicinal marijuana – it has never been shown to be safe or effective as a medicine.'
He reiterated this statement on May 25, 2017, claiming that "marijuanna is not medicine" during a visit to the Cleveland Clinic in Cleveland, Ohio. He added:
'If it turns out that there's something in smoked marijuana that helps people, that's awesome. I will be the last person to stand in the way of that... But let's run it through the Food and Drug Adminstration process, and let's stick to the science on it.'
Some drug reformers gave Rosenberg a pass when he was promoted. “Let’s hope he’s in line with the political consensus in favor of scaling back mass incarceration and the worst harms of the drug war,” Bill Piper, director of national affairs for the DPA, said at the time.
However, Vox.com reported that during his tenure in Virginia, "Rosenberg unapologetically enforced mandatory minimum sentences for crack cocaine that contributed to the wide sentencing disparities between black and white Americans."