Trump on marijuana legalization. BI Graphics

Election Day was a watershed moment for marijuana legalization.

Recreational marijuana is now legal in seven states — Maine has yet to be called — as well as Washington D.C. 24 states have varying forms of medical marijuana laws on the books.

President-elect Donald Trump will have to reckon with this issue when he takes office on January 20.

Trump has flip-flopped somewhat on this issue throughout his public life.

Recently, Trump has supported state's rights to choose how to legislate medical marijuana, but has not expressly called for legalization.

"In terms of marijuana and legalization, I think that should be a state issue, state-by-state," Trump told The Washington Post. "… Marijuana is such a big thing. I think medical should happen — right? Don’t we agree? I think so. And then I really believe we should leave it up to the states."

He has also expressed support for medical marijuana, telling Bill O'Reilly in February that he's, "in favor of medical marijuana 100%."

"I know people that have serious problems and they did that they really — it really does help them," Trump said.

Trump on weed. BI Graphics

But, Trump also called Colorado's legal marijuana industry a "real problem," in the same interview with O'Reilly, a departure from his position in 1990, when he told The Miami Herald that the US needs to "legalize drugs to win" the war on drugs.

And, Mike Pence, Trump's running mate, has expressed his opposition to marijuana legalization and governs a state with some of the harshest marijuana-sentencing laws.

While many experts have called Election Day a "tipping point" in the battle to legalize marijuana federally, others on the anti-legalization side are cheering for a Trump win.

"President-elect Trump has promised to be a law-and-order president," Kevin Sabet, the co-founder of Smart Approaches to Marijuana, one of the largest anti-legalization groups, told Business Insider. "I'm feeling much better than I thought I might."

Trump hasn't taken a definitive stance on the issue, according to the campaign's website. For its part, the Marijuana Policy Project gives Trump a "C+" grade on marijuana legalization.