The Justice Department (DOJ) filed suit Monday to block a controversial California law that seeks to place conditions on the sale or transfer of federal lands within the state.

The law, known as SB 50, purports to prevent county and state employees from recording the transfers of deed of federal public land unless a California commission is given a “right of first refusal” to arrange the transfer to its own chosen entity, presumably the state itself.

Environmental groups widely see the law, which came into effect at the beginning of the year, as a way of preventing the federal government from selling land for resource-extraction and other private development. In California, as in many western states, the status of federal public lands is no minor matter. According to the General Services Administration’s Office of Governmentwide Policy, more than 45 percent of the area of California is owned by the federal government.

In its 17-page complaint, the federal government is relying on the U.S. Constitution’s Supremacy Clause, as well as the lesser known Property Clause (“Congress shall have Power to dispose of and make all needful Rules and Regulations respecting the Territory or other Property belonging to the United States”) to prevent the burdening of federal land sale plans with Californian red-tape.

“I regret the need to file yet another lawsuit against the state of California today,” Attorney General Jeff Sessions said in a statement on the filing of the suit. “[O]nce again, we see that too many of our resources are being diverted to deal with meritless and unnecessary lawsuits.”

The complaint argues that SB 50 in essence discriminates against the federal government and creates a “cloud on marketable title” because buyers will have to seek the stamp of approval from California’s land commission if they want to record their deed. Not having a deed of transfer recorded creates serious problems for a land owner.

SB 50, however, is a cleverly written statute that avoids some obvious constitutional pitfalls. Rather than directly assert any power over the federal government, it denies title recording to the private buyer who owns land – after the sale – as a private California citizen. It is California’s own civil servants, their county recorders, who are compelled to seek a commission stamp of approval for the sales. And finally, because the requirement is merely a “right of first refusal,” it should not directly affect the price at which the federal government can sell land.

The federal complaint, fronted by Jeffrey Wood, Acting Assistant Attorney General of the DOJ’s Environment and Natural Resources Division, posits the cloud on marketable title created by the new duty placed on a buyer if they want their deed recorded like in any typical land purchase, is enough to invalidate the California law on constitutional grounds.

Attorney General Sessions placed the lawsuit in the context of the mass of litigation in which his DOJ finds itself entangled with California. “We are forced to spend our resources to bring these lawsuits against states like California that believe they are above the law and are passing facially unconstitutional laws specifically intended to interfere with the federal government’s ability to carry out its legitimate law enforcement duties,” he said, making reference to, for example, the cases on California’s sanctuary laws, the Deferred Action for Childhood Arrivals (DACA) rescission, and the Trump administration’s travel ban executive orders, all of which began in the California federal courts.