The move means that prosecutors within the U.S. attorney's office in the District could bring more cases if so directed by Jessie K. Liu, who was picked as the city's top prosecutor by President Trump.
The District has seen a drop in marijuana possession cases since residents voted in 2014 to allow adults 21 or older to possess up to two ounces of the drug and smoke in private quarters. In 2010, according to figures from the U.S. attorney's office, there were 4,599 arrests involving marijuana in D.C. Superior Court. That number dropped to 276 arrests in 2015 after the new law went into effect. Last year, there were 587 arrests.
People familiar with the office say prosecutors have spent more time focusing on cases involving large-scale marijuana distribution or trafficking and those with links to violent crime.
"I would be surprised if anything really changes under this new policy," said Channing D. Phillips, the District's former U.S. attorney who served from 2015 to 2017. "I don't see a return to the office prosecuting simple marijuana possession cases. The focus will be on traffickers and large organized crime. But not simple possession. The law in D.C. allows for personal use."
In a memo sent to U.S. attorneys Thursday, Sessions noted that federal law prohibits the possession and sale of marijuana, and he undid several Obama administration memos that advised against bringing marijuana prosecutions in states where it was legal to use the drug for recreational or medical purposes. Sessions said prosecutors should use their own discretion — taking into consideration the department's limited resources, the seriousness of the crime and the deterrent effect that they could impose — in weighing whether charges were appropriate.
The District's marijuana law, which went into effect in February 2015, prohibits smoking marijuana in public spaces and allows users to grow up to six marijuana plants — no more than three of which are mature — in their homes. The law also prohibits the sale or transfer of marijuana above one ounce in exchange for money, goods or services.
In a statement, William Miller, a spokesman for Liu's office, said the prosecutors will use "discretion" in selecting which cases it pursues.
"The U.S. Attorney's Office for the District of Columbia is committed to reducing violent crime and dismantling criminal gangs and large-scale drug distribution networks that pose a threat to public safety. In accordance with the Attorney General's memo, we will utilize long-established principles of prosecutorial discretion in pursuing cases and fulfilling that commitment," Miller said. The office declined to comment further.
In Maryland, lawmakers are also watching the impact on marijuana users, especially those who have relied on marijuana for medicinal purposes and have had the drug prescribed by physicians.
Maryland Del. Jeffrey D. Waldstreicher (D-Montgomery) tweeted Thursday "more than 20k folks have applied for medical cannabis. Once again @realdonaldtrump and AG Sessions have revealed their innate cruelty."
Joy A. Strand, executive director of the Natalie M. LaPrade Maryland Medical Cannibus Commission, said the group will "carefully evaluate any federal directives" and will "continue on the strategic path to establish a robust medical cannabis program for Maryland patients in need."
Federal prosecutors in Maryland referred calls to the Department of Justice.
In Washington, marijuana legalization supporter Adam Eidinger, a co-founder of D.C. for Marijuana Justice, or DCMJ, noted that Congress had an opportunity to overturn the 2014 vote by District residents, but chose not to do so.
"This isn't just D.C. law. This was the will of the people. This was a law that was approved by the voters. Congress granted us authority over certain laws and Congress did not overturn it," Eidinger said. Eidinger, who has been arrested 21 times for marijuana possession, including twice last year, said prosecutors dropped both of the recent cases.
Defense attorneys in the District said that although they do not believe it is likely there will be more aggressive prosecution of lower-level marijuana cases in D.C. Superior Court, they think prosecutors could seek to pursue more distribution cases in federal court.
"I can't imagine the federal court wanting to federally prosecute people for anything short of huge distribution," said Heather Pinckney, a defense attorney in Washington.
"We are in such a bubble, which is good. With our prosecutors, to their credit, weed is not their beef. Their focus is on PCP and heroin and conspiracy cases," she said. "A little amount of weed is not their focus, and I don't think that will change. They have too many other things to worry about."
Aaron Gregg and Lynh Bui contributed to this report.