Mayor Daniel Lurie might be trying to avoid a verbal confrontation with President Trump, but City Attorney David Chiu came out swinging Tuesday about this National Guard business.

The City of San Francisco joined a coalition of 109 mayors and other city and county officials in filing an amicus brief with the Supreme Court on Monday, urging the high court to stop the deployment of National Guard troops in Chicago — in the case called Donald Trump, et al v. State of Illinois.

The brief, a copy of which can be found here, argues that, “As in other jurisdictions, by federalizing the National Guard in Chicago, the Government failed to meet statutory thresholds and threatens to trample the foundational principles forbidding federal military involvement in civilian law enforcement.” And the coalition of cities notes that Trump has threateningly said “we’re gonna have troops everywhere,” in a massive, dangerous, and unprecedented use of the National Guard to do his bidding in a game of political theater.

“Needlessly and haphazardly deploying the military to American cities makes us all less safe,” said SF City Attorney David Chiu in a statement. “These deployments inflame tensions, undermine local law enforcement, and harm local economies. We are joining local jurisdictions across the country to defend the rule of law and our right to peace and safety.”

Chiu added, “We urge the Court to uphold the bedrock legal principle that domestic law enforcement is not the military’s job.” And, he vowed, “Should President Trump make good on his ridiculous threats to send the military to San Francisco, our city is prepared, and my office is prepared to take the necessary legal action to defend San Francisco.”

The brief came on the same day that the Ninth Circuit Court of Appeals ruled in favor of the Trump administration in its effort to force a National Guard deployment in Portland, Oregon — following a monthslong, mostly peaceful protest outside the federal building there.

Chiu goes on to note the very low crime SF is experiencing right now, emphasizing the “70-year low in homicides and a 22-year low in car break-ins.” And noted that the 50,000-person “No Kings” protest over the weekend occurred “without incident.”

“Federalizing the National Guard or domestically deploying the military should be an absolute last resort where local resources are truly overwhelmed,” Chiu’s office says. “The presence of unwanted military troops can interfere with local law enforcement’s chain of command, deployment structures, and de-escalation strategies.”

SF District Attorney Brooke Jenkins also said last week that she “won’t hesitate” to bring excessive force charges against federal troops if that becomes an issue with any hypothetical arrival of those troops.

Mayor Daniel Lurie has been more measured in his public comments, issuing a statement Monday saying only that, “the National Guard does not have the authority to arrest drug dealers — and sending them to San Francisco will do nothing to get fentanyl off the streets or make our city safer.”

Monday’s amicus brief was joined locally by the cities of Alameda, Anaheim, Long Beach, Los Angeles, Sacramento, and San Jose, and also by the cities of Boston, New York, Minneapolis, and about 100 others.

Related: Trump-Appointed Judges on Ninth Circuit Side With Trump, Allowing National Guard Troops to Be Sent to Portland

Top image: Photo via SF City Attorney’s Office