The booming business of legalized marijuana may be seeing a favorable shift from the Trump administration. Attorney General nominee William Barr's testimony this week signaled potential relief for business owners in states that have enacted various laws legalizing cannabis products.

Marijuana remains illegal under federal law, and there's no consensus in Congress on a recent proposal to change that.

In front of the Senate Judiciary Committee on Tuesday, Barr said he doesn't plan on using federal resources to "go after" companies if they are complying with state law. That would be a reversal from the approach taken by his predecessor, former Attorney General Jeff Sessions, who vowed to pursue federal violations more aggressively.

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According to Erik Altieri, executive director of the National Organization for the Reform of Marijuana Laws (NORML), Barr's stance is a good sign for advocates but it remains to be seen if his actions will follow through on his pledge.

"It's encouraging but we do need to remain vigilant to keep him to hold his word to the American people," Altieri told CBSN's Reena Ninan. His organization is a non-profit that supports responsible pro-marijuana policy.

While 10 states and Washington, D.C. have legalized recreational adult use of marijuana, and more than 20 other states allow some medical uses, U.S. attorneys can still prosecute its possession and sale under federal law. Last year, Sessions reversed an Obama-era policy that encouraged federal prosecutors to take a hands-off approach in states where marijuana is legal. This put business owners back at higher risk of coming under federal scrutiny.

While Barr's stance may seem like a departure from his previous get-tough approach to drug policy, he made it clear during his testimony that he doesn't support federal legalization.

"I think it's a mistake to back off on marijuana," said Barr. "However, if we want a federal approach, if we want states to have their own laws, then let's get there and let's get there the right way." He said Department of Justice policy should align with congressional legislation.

Altieri agrees that the federal government's official acknowledgment of state legislation should be in the hands of Congress, and he urged lawmakers to embrace what he sees as popular support for legal pot among Americans.

"There's no putting the toothpaste back in the tube on this one. The American people want to end our failed prohibition and any attempts to really slow that down or stop it will be incredibly unpopular across all party lines and demographics," Altieri said.

Altieri also argues that federal marijuana legalization would help address many of the issues that concern people about marijuana's potential risks.

A recent book by by Alex Berenson, "Tell Your Children: The Truth About Marijuana, Mental Illness, and Violence," highlights some of those risks, including marijuana's links to mental illness, harder drug use, and violence. Berenson argues that legislation and public perception in the U.S. have sped ahead of the science, and that "the growth has happened in the face of powerful new evidence that marijuana can be deeply harmful to mental health."

When asked about Berenson's warnings, Altieri said legalization would give the government greater ability to address these concerns.

"That is not a knock against legalization if you have concerns about it. Prohibition is defined by the absolute lack of control of marijuana. If you have concerns about its use, particularly with youth and other health concerns, the answer is to regulate it and have those controls — not to leave it in the hands of criminal elements completely unregulated in back alleys and street corners."