After Missouri voted to legalize medical marijuana in November 2018, the state’s new Republican governor, Mike Parson, moved quickly to certify tens of thousands of patients and begin licensing cannabis businesses.

But what seemed at first to be an easy source of voter satisfaction and a new cache of revenue to the state has boomeranged badly: A flood of complaints led to state and federal corruption probes that now threaten Parson’s 2020 campaign.

The governor’s close personal friend and fundraiser, Steve Tilley, is at the center of the probes. He represented lucrative clients who appeared to receive a boost in the licensing process. The campaign of Parson’s presumptive Democratic opponent, State Auditor Nicole Galloway, put out a taunting memo declaring, “Where there’s smoke, there’s fire.