After decades spent operating in the shadows, the ever-growing legal marijuana industry has begun supporting federal campaigns and lobbying efforts in Washington DC.

For an industry that remains illegal under federal law, taking action at the federal level — in the form of contributions from industry heavyweights, and the formation of the first and only political action committee for the industry — is a critical step in achieving legitimacy. It also signals that elected officials, who in the past were unwilling to accept money from anyone in the weed business, are responding to the interests of voters.

"My impression is that political contributions are part of a broader pattern of the industry coming into its own," Congressman Earl Blumenauer, a Democrat from Oregon, told VICE News. "Lobbying, advocacy, and participating in politics — they're doing what virtually every other interest group has done in the past. It's the maturing of the industry, the evolution of the industry."

Blumenhauer has long been a supporter of legalizing adult use of the drug, and readily accepts campaign contributions from the marijuana industry.

"In the last five years the issue has just taken off," Blumenauer said. "Twenty-three states have legalized medical marijuana, most were the result of voter action. It has a different feel to it because it's driven by the public."

For years, organizations aiming to end the failed war on drugs in favor of an evidence-based approach to narcotics policy have lobbied Washington. The Drug Policy Alliance, National Organization for the Reform of Marijuana Laws (NORML), American for Safe Access, are just a few examples of groups working to reform federal pot laws.

Only recently has the marijuana industry — a group with interests that are distinctly separate from medical marijuana and social justice movements — attempted to influence policy in DC. While other groups have campaigned on behalf of medical patients or to end the war on drugs because of its corrosive and destructive effect on African-American and Latino communities, the pot industry seeks to profit from changes to the law.

"There's been a big change, a very real shift in visible public opinion toward making this [marijuana] a legal, regulated product," said Taylor West, deputy director of the National Cannabis Industry Association (NCIA). "We're trying to establish the idea that this is a legit industry, following the rules, and the more we can show that reality, the less likely they [politicians] are to have a reactionary approach. That's a big reason to have an industry association."

'This is an issue that should cut across all political parties, and I'm not interested in seeing it become a political football.'

Banking is one issue of importance to the NCIA. Despite a federal announcement that banks and credit unions could open and accounts, and do other business with the pot industry, the vast majority of financial institutions around the country are still unwilling. Current policies make it difficult for cannabis businesses to process credit cards and pay employees, and doing business using mostly cash carries security risks.

But, with only a single industry-related political action committee (PAC) in Washington DC at the moment, the hundreds of millions that other industries and interest groups spend through their PACs every year dwarfs the marijuana industry's war chest of just $43,650.

Unlike Congressman Blumenauer, many politicians don't want to talk about money they've received from the marijuana industry. A report from Associated Press on marijuana-related political contributions described a dozen candidates either declining interview requests or not returning calls.

Steve DeAngelo, executive director of Harborside Health Center, a large medical marijuana shop in Oakland, told VICE News that he's never encountered a politician who refused to take contribution from him. However, he pointed out that he and his business are "very careful about who we donate to."

"We give to candidates who are going to support the issue," DeAngelo said. "This is an issue that should cut across all political parties, and I'm not interested in seeing it become a political football."

There's nothing specific in federal election laws that prevents politicians from accepting contributions from the marijuana industry, according to a Federal Election Commission spokesman.

Taking money from illicit sources — of which the marijuana industry used to be considered — is a political problem, not a legal one, according to Ken Gross, a lawyer with years of experience representing clients involving the FEC.

"It's not their [the FEC's] jurisdiction, and it's not in and of itself an election law violation to take money obtained by unlawful means," Gross told VICE News.

Even if the principle players involved in a legal marijuana business were targeted by a federal investigation and ultimately convicted on drug charges, politicians would likely not have to return the funds either.

Gross explained that the only case in which campaigns can sometimes be compelled to return contributions stemming from illegal activity is in instances where there's monetary damage to a person — defrauding investors out of cash, for example.

Otherwise, when it comes to crimes against society — such as illegal narcotics production and trafficking — the government has no real grounds to seize money contributed to politicians. "You can't get blood from a turnip," Gross said.

Follow Max Cherney on Twitter: __@chernandburn