President Donald Trump appears to be making good on threats to use federal authority to intervene in California’s homelessness crisis, which has made large portions of San Francisco and Los Angeles unhealthy and unsafe.

The Washington Post reported Tuesday that the White House is planning a “crackdown”:

President Trump has ordered White House officials to conduct a sweeping crackdown on homelessness in California, citing the state’s growing crisis, according to four government officials aware of the effort.

The talks have intensified in recent weeks. Administration officials have discussed using the federal government to get homeless people off the streets of Los Angeles and other areas and into new government-backed facilities, according to two officials briefed on the planning.

The Post adds that “it is unclear how they could accomplish this and what legal authority they would use.” In fact, it is quite clear how Trump could do it under existing law. The president could invoke the National Emergencies Act of 1976 to declare an emergency, and could also invoke the Robert T. Stafford Disaster Relief and Emergency Assistance Act of 1988, which allows a president to override state authorities and bring in the Federal Emergency Management Agency (FEMA) if “he [the president] determines that an emergency exists for which the primary responsibility for response rests with the United States because the emergency involves a subject area for which, under the Constitution or laws of the United States, the United States exercises exclusive or preeminent responsibility and authority.”

Earlier this year, Trump warned that the homelessness crisis had become so severe in California that the federal government might have to intervene. Gov. Gavin Newsom and Los Angeles Mayor Eric Garcetti pushed back, suggesting that the problem was not their fault and that it would require federal funding, not intervention.

However, a recent outbreak of typhus in downtown Los Angeles has raised public alarm. Dr. Drew Pinksy warned in July that Los Angeles was at risk for an outbreak of bubonic plague, which is endemic among rodents in the area but could easily spread to humans through fleas, given unsanitary conditions in the center of the city. Pinsky said then that he was not quite ready to declare the situation an “emergency,” put that he was “ready to pull that trigger.”

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He earned an A.B. in Social Studies and Environmental Science and Public Policy from Harvard College, and a J.D. from Harvard Law School. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.