Governors from four states where recreational marijuana is legal for adult use sent a letter to Attorney General Jeff Sessions and Treasury Secretary Steven Mnuchin on Monday urging them to respect state cannabis laws.

The letter, signed by Alaksa Gov. Bill Walker, Colorado Gov. John Hickenlooper, Oregon Gov. Kate Brown and Washington Gov. Jay Inslee, implores the administration to continue the policy set by a 2013 Justice Department memo allowing state marijuana laws to go into effect without federal intervention. Sessions, a longtime critic of marijuana use, has indicated his department may reverse that Obama-era policy and begin cracking down on state-level legalization efforts.

“As governors of states that have legalized marijuana in some form, we ask the Trump Administration to engage with us before embarking on any changes to regulatory and enforcement systems,” the letter reads. “The balance struck by the [DOJ memo] has been indispensable ― providing the necessary framework for state regulatory programs centered on public safety and health protections.”

“We understand you and others in the administration have some concerns regarding marijuana,” the letter continues. “We sympathize, as many of us expressed apprehensions before our states adopted current laws. As governors, we have committed to implementing the will of our citizens and have worked cooperatively with our legislatures to establish robust regulatory structures that prioritize public health and public safety, reduce inequitable incarceration and expand our economies.”

The governors’ letter earned praise from Aaron Smith, the executive director of the National Cannabis Industry Association.

“There is no denying that regulated cannabis businesses are preferable to underground markets dominated by gangs and cartels,” he said in a statement. “The regulated markets are creating jobs, generating tax revenue, and taking marijuana sales off the streets. The Trump Administration should be working with the states to ensure the regulated markets are functioning properly and safely, not working against the states to shut them down.”

But Kevin Sabet, who runs the anti-legalization group Smart Approaches to Marijuana, argued that legalization impacts surrounding states and thus should be subject to federal regulation.

“While we don’t want to see state employees arrested for implementing state laws, or people locked up or given criminal records for smoking pot, we support federal laws against marijuana. It’s time to end, not expand the special interest big marijuana lobby,” he said in a statement. “That lobby would like us to ignore the fact that today’s legalized marijuana ― and the accompanying industry ― is damaging to public health.”

While 26 states and the District of Columbia have legalized marijuana use in some form, the substance is still banned at the federal level.

A package of reform bills introduced in Congress last week would seek to close the gap between state and federal policy by removing cannabis from the DEA’s list of most dangerous substances and instead regulating the substance similarly to alcohol.

The sponsors of the reform package, Sen. Ron Wyden (D-Ore.) and Rep. Earl Blumenauer (D-Ore.), argued that doing so would be in line with public opinon: Polls show a majority of Americans now support legalization efforts. They also argued the legislation would reduce incarceration and increase federal revenue.