An ex-chief of the Seminole Tribe, with a legendary history of wrangling regulators as he pioneered the casino industry on tribal lands, plans to help other Native American groups grow and sell tax-free marijuana in states where it’s legal.

James Billie, a Vietnam veteran has launched a finance firm called MCW to provide financing and legal counsel to other tribes to help them produce marijuana on their lands, in accordance with state law.

“Wherever it’s legal, that’s where we’re going, where the other Native Americans are,” said Billie, in an interview with CNNMoney.

Recreational marijuana is legal in eight states and medical marijuana is legal in 29 states, including Florida, home of the Seminoles. But Billie said he won’t be growing weed on tribal land in the Everglades because Florida’s marijuana laws are too restrictive. Instead, Billie has teamed up with Electrum Partners, a finance firm specializing in the legal marijuana industry, to seek out tribes in states that have good land for growing weed.

Billie and Electrum see dollar signs in this burgeoning cannabis industry, which is estimated to exceed $21 billion in nationwide annual sales by 2020, according to New Frontier Data, a company that analyzes the industry. They want to focus on all aspects of it, from medical uses to hemp.

Electrum Partners president Leslie Bocskor, of Las Vegas, said he’ll help the tribes navigate the complex regulations of the marijuana market, which remains illegal under federal law.

“The real issue isn’t the money; the real issue isn’t the business,” Bocskor said to CNNMoney. “The real issue is the structure that makes sure you do this in a way to make sure you don’t have an issue from a regulatory perspective.”

To get marijuana production running on tribal lands, Bocskor will have to sort through a maze of tribal, state and federal laws regarding the sale of controlled substances and the introduction of new commercial ventures. Also adding to the potential legal pitfalls, Attorney General Jeff Sessions has said he opposes the legalization of marijuana, though he’s never detailed what he intends to do about it.

Bocskor, who has invested in the legal marijuana industry in his home state of Nevada, said he’ll begin with investments of $25 million to $50 million in Native American tribes, hoping to expand those investments up to $300 million within three years. But he and Billie have yet to make a deal with any specific tribe, in any particular state.

The venture could prove to be lucrative. Under federal sovereignty laws, Native American tribes do not have to pay federal income tax on casino or other business revenue and they can chose whether or not to levy sales tax, a draw for non-Indian customers. Billie says marijuana sales could be tax free under these rules, allowing consumers in states like Washington and Colorado to avoid the hefty sales taxes usually associated with marijuana products.

Bocskor has chosen a strategic partner in Billie, who was chairman of the Seminoles from 1979 to 2001 and again from 2011 to 2016, but not just because he’s a tribal leader. Billie has past experience in working out controversial deals with government regulators to reap financial benefits for his tribe. This experience could be valuable in navigating the marijuana industry, he said.

Billie began his 27-year tenure as chief of the Seminoles in 1979 and since then he has cut his teeth on another “sindustry”: gambling. The chief helped to establish big stakes bingo on tribal lands, including Seminole Casino Classic, a sprawling facility in the Miami suburb of Hollywood, where the tribe also established Seminole Hard Rock Hotel & Casino.

State officials didn’t like the idea of $100,000 bingo jackpots and tried to shut them down as a violation of state law, which limits the size of jackpots. But the Seminoles fought for their bingo casinos in court, on the basis of tribal sovereignty, and won.

Thus began a long political and business career for Billie, who was courted in 1996 by now-President Trump, who was trying to make deals with Native American tribes to include them in his casino empire.

“No deal was ever done, but President Trump was very nice and gave excellent suggestions,” said Billie.

Marijuana is a whole new industry for Billie, who said he doesn’t even smoke pot.

“I have tried it; it didn’t work out,” he said, when asked if he ever inhaled.

Even still, he sees the potential for big profits.

“This is going to be bigger than bingo,” said Billie.