Governors from the first four states to legalize recreational marijuana are asking the Trump administration to let the cannabis experiments continue.
The governors of Alaska, Colorado, Oregon and Washington say that marijuana legalization has expanded their economies.
The governors also say in Monday's letter that legal weed can be regulated to protect public safety and that legalization reduces "inequitable incarceration," or people of color being disproportionately jailed for pot crimes.
The letter was addressed to Attorney General Jeff Sessions and Treasury Secretary Steve Mnuchin. The governors say they opposed legalization at first, but warn that a federal pot crackdown now "would divert existing marijuana product into the black market."
The governors also ask for the Treasury Department not to change instructions to banks for handling marijuana money.