It’s fitting that John Oliver would kick off April—the month of stoners’ favorite holiday (4/20)—by taking on outdated marijuana laws in the US.

Though 30 states currently allow for cannabis use for medical or recreational purposes, the US federal government still classifies it as a schedule 1 drug—a controlled substance with high risk of abuse and no medical use, right up there with heroin. “Marijuana is not a schedule 1 any more than a hedgehog is an apex predator,” Oliver said on the April 2 episode of Last Week Tonight.

Beyond pot enthusiasts, Oliver framed marijuana decriminalization as a broader public good. He pointed out that blacks in the US are more than four times more likely to be arrested for marijuana possession than whites are, and described the “War on Drugs” as having racist roots.

Oliver argues that marijuana became the focus of major law enforcement because of Richard Nixon was looking for a way to criminalize minorities and the anti-war left. Recordings from 1971 show Nixon heavily associated marijuana with Jews, for example:

You know, it’s a funny thing. Every one of those bastards that are out for legalizing marijuana is Jewish. What the Christ is the matter with the Jews, Bob? What is the matter with them?

Citing examples in the news, Oliver showed how the US’s outdated pot laws can prevent cannabis-related businesses from opening up bank accounts, jeopardize people’s careers even if they have valid medical reasons for using cannabis, and have families broken up by child-protective services if a parent has marijuana plants.

During Obama’s administration, the former US president had publicly said the federal government wasn’t “going to spend a lot of resources trying to turn back decisions that have been made on the state level,” and US marijuana advocates saw several electoral victories in November. But now legal weed could be under attack by new attorney general Jeff Sessions, who not only has called cannabis ”dangerous” but has also said that “good people don’t smoke marijuana.”

“Marijuana laws affect everything from environmental regulations to international treaties,” said Oliver. “And ideally, we should also go back and expunge records of people convicted of low-level marijuana offenses in the past. And all of this I know is a lot of work, which is why we should really start right now because I would argue that it is absolutely worth it.”