Speaking at a town hall in Las Vegas on Saturday, the 2020 Democratic presidential candidate said whether the U.S. should legalize cannabis on a federal level is still up for debate as far as he is concerned.

“The truth of the matter is, there’s not nearly been enough evidence that has been acquired as to whether or not it is a gateway drug,” Biden said, according to Business Insider. “It’s a debate, and I want a lot more before I legalize it nationally. I want to make sure we know a lot more about the science behind it.”

Biden, as he has throughout his time on the campaign trail, said he supports medical marijuana and insisted possession of the substance “should not be a crime.”