Donald Trump has made his independence from Super PACs and political donors a big part of his presidential campaign, but he just earned the endorsement of an influential billionaire who could seriously impact his stance on a big issue for Millennials.

This is billionaire Sheldon Adelson. He's a billionaire and a major opponent of marijuana.

Flickr/East Coast Gambler - flickr.com

He also just announced that he'd be supporting Trump's campaign for President.

Adelson has accrued massive wealth and political influence through his various casino enterprises, and he has a history of using that influence to fight against marijuana legalization.

He helped fund a campaign against Florida's medical marijuana initiative in 2014.

Washington Post - washingtonpost.com

He also pressured the Las Vegas Review-Journal to reconsider its stance of supporting marijuana legalization.

The Daily Beast has called Adelson the one man who could halt GOP support for marijuana reform.

Daily Beast

While Trump has frequently spoken about his financial independence during the GOP primary, he recently announced he will not be self-funding his general election campaign and will accept outside money.

Adelson is known for throwing a lot of money into the presidential race, so he could be in line to give Trump a big funding boost. If that happens, it's possible Trump will be pressured to take a stance against marijuana.

Adelson hasn't ever clearly expressed why he opposes marijuana legalization, but The Daily Beast reported he appears to think marijuana is a gateway drug and also wants to protect his interest in selling alcohol at his casinos.

Where does Trump stand on Marijuana now?

Trump has publicly supported medical marijuana, and the Marijuana Policy Project gives him a C+ for his stance on the issue.

Marijuana Policy Project - mpp.org

In the past, he even called for full legalization.

"We’re losing badly the War on Drugs," he told the Miami Herald. "You have to legalize drugs to win that war. You have to take the profit away from these drug czars.”

Trump's position has become a little more nuanced since then.

"In terms of marijuana and legalization, I think that should be a state issue, state-by-state. … Marijuana is such a big thing," Trump said at a rally in October. "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 also voiced support for medical marijuana during an MSNBC town hall in March. "I've heard some wonderful things in terms of medical [marijuana]," he said.

Paul Armentano, deputy director of the marijuana advocacy group NORML, told ATTN: he isn't sure if Adelson will influence Trump's marijuana position or not, but he said the two do appear to have conflicting beliefs. He said Adelson's opposition to Florida's medical marijuana initiative "would appear to be at odds with some of Trump's recent public statements, where he has said he is supportive of medical marijuana."

"Because Trump seems to have flip-flopped over the years on a number of positions, including his positions on drug policy, I can't as an outside observer speculate as to how wed he is to the positions he's holding at the moment," he said.

Armentano noted that it would probably be a bad idea for Trump to come out against medical marijuana, because it's popular among Americans. Medical marijuana has support from 81 percent of Americans, and 61 percent support legalizing marijuana for recreational use.