The president has frequently criticized Sessions, particularly over his decision to recuse himself from oversight of the federal investigation into potential collusion between Trump's 2016 presidential campaign and Russian Federation.
"I believe in states' rights; and the other day, the president notified me that he would be supporting a states' rights approach when it comes to legalized marijuana", Gardner said on "The Daily Briefing" Friday.
Gardner was angered in January when Attorney General, Jeff Sessions, revoked the Obama-era Cole memo that discouraged the federal government from interfering with states that had legalized marijuana.
In a statement Friday, Sen.
And Gov. Jay Inslee tweeted of the report, "This is welcome news, if true". "We're consulting Congress about issues including states' rights of which the president is a firm believer and the statement that the senator put out earlier today is accurate", she said.
White House Press Secretary Sarah Huckabee Sanders confirmed Gardner's account of the president's thinking - but Sessions' reaction was not immediately known.
Gardner noted that Trump had stated during his campaign that he had supported states' rights to decide how to approach marijuana.
Former House Speaker John Boehner, a staunch anti-legalization lawmaker, made the decision to change course on cannabis after he joined the board of directors of Acreage Holdings, a New York-based cultivator that operates in 11 states. I am cautiously optimistic that the president appears to have heard the will of the people on this issue. "I remain committed to keeping cannabis in the state of OR, but out of the hands of children, while protecting the will of Oregonian voters, who overwhelmingly support the legal cannabis industry and the jobs it creates".
Trump and Sessions have had moments of friction in their relationship for months, on issues unrelated to the legality of marijuana.
When he selected Sessions, a former federal prosecutor and USA senator from Alabama, as his attorney general, marijuana supporters girded themselves for a crackdown. However, Gardner mentioned he had been promised by Sessions he'd do absolutely nothing to interfere with the robust bud market of Colorado.
Sessions once said he thought the Ku Klux Klan was "OK until I learned that they smoked pot", though he later claimed to be joking.
In retaliation, Gardner used his power as a senator to prevent consideration of any nominees for the Department of Justice - an extraordinary step for a senator against an administration run by another member of his own political party.
Some of Gardner's fellow GOP senators groused at the impact of the hold, and Gardner allowed some nominees to proceed in a "good-faith" gesture last month.
The action came amid widespread speculation that Trump will remove Justice officials overseeing the Russian Federation investigation.
President Donald Trump has assured a top Senate Republican that he will allow states to pursue marijuana laws as they see fit, seemingly bringing an end to tense speculation that his administration could be preparing to mount a crackdown on state-legal cannabis operations.