The amount of money spent on medical marijuana in the next four years will nearly double, according to a new study. But that could change should Donald Trump’s Administration decide to step in.

Sales of Marijuana could exceed $681 million nationwide by 2020.

Retail sales this year are pegged at $367 million, according to a report by New Frontier Data and ArcView Market Research.

While that’s good news for operators, there’s still one big unknown: the new administration in Washington.

Marijuana is still illegal under federal law.

President-elect Trump has nominated Alabama Senator Jeff Session to head the Department of Justice. And Sessions has been openly critical of the DOJ for not enforcing federal laws.

The lead researcher for New Frontier Data believes that if Sessions is confirmed and takes a tougher stance than his predecessors, it is likely he would focus on recreational marijuana laws and not medical marijuana.