The next U.S. attorney general is going to have to respect the decision of Colorado and other states to legalize recreational and medical marijuana — at least if Republican Sen. Cory Gardner has his way.

“Whoever comes after him is going to face some pretty tough questions about where they stand on states’ rights and making sure they will stand up for states’ rights,” Gardner told The Denver Post on Thursday. “I am going to demand that the new attorney general side with the president because the president is right on states’ rights.”

Gardner blocked President Donald Trump’s nominees to the Justice Department for three months in early 2018 after Attorney General Jeff Sessions rescinded something called the Cole Memorandum, an Obama-era policy that outlined a set of rules for states that legalized marijuana to follow if they wanted to avoid federal intervention.

“I obviously had my differences with Attorney General Sessions, particularly as it related to the Cole Memorandum,” Gardner said.

He ended his blockade in April after talking to Trump on the phone and getting what he described at a commitment to protect Colorado and other states where marijuana is legal.

When asked what should happen to the investigation by special counsel Robert Mueller into possible coordination between the 2016 Trump campaign and Russia, Gardner said it should “absolutely continue,” adding that “the president has said he wants it to continue.”

But Gardner was less certain about whether he’d support a bill to protect the investigation, which his outgoing colleague, Sen. Jeff Flake, R-Arizona, says he will try to pass before leaving office.

Sen. Michael Bennet, a Colorado Democrat, was clear about his position on Twitter.

“Our institutions are being tested,” he wrote after the news of Sessions’ resignation broke. “The Senate Majority must stand up for the rule of law instead of cowering from its responsibility as an independent check on this President and his effort to undermine the Mueller investigation.”