What was once a crowded Democratic presidential race has winnowed down to two major candidates: Sen. Bernie Sanders (I-VT) and former Vice President Joe Biden. For marijuana reform advocates, the stakes are high.

While the opponents diverge on a variety of issues, cannabis legalization represents one of the clearest examples of their ideological divide.

Put simply, Sanders was one of the earliest proponents of the reform move, becoming the first major presidential candidate to call for federal legalization in 2015 and filing the Senate’s first-ever bill to deschedule cannabis under federal law. In his current campaign, he’s included a legalization plank prominently in his platform with a pledge to take bold executive action early in his administration.

Biden, meanwhile, played a key role in enacting punitive anti-drug laws during his time as a senator, and he’s maintained opposition to legalization even as the vast majority of his party has come to embrace the policy change. That said, at a time when polls show that the vast majority of Democratic voters support ending cannabis prohibition, he has begun to embrace some modest reforms during the course of the campaign.

The issue didn’t come up at the two candidates’ first head-to-head debate on Sunday, but given the significant public interest in marijuana reform, those differences are sure to be highlighted in the weeks to come. For the time being, however, here’s an overview of the Sanders-Biden drug policy divide.