After a San Francisco supervisor got a resolution passed last week declaring the National Rifle Association a "domestic terrorist organization," the notoriously vocal gun group has shot back with a lawsuit.

The suit, filed Monday in the U.S. District Court for the Northern District of California, says that the Board of Supes' resolution violates the NRA's First Amendment rights by seeking to blacklist anyone who supports the organization. The suit asks the court "to instruct elected officials that freedom of speech means you cannot silence or punish those with whom you disagree," as the Associated Press reports.

Supervisor Catherine Stefani penned the resolution, passed at the September 3rd Board of Supervisors' meeting, states that the NRA "spreads propaganda that misinforms and aims to deceive the public about the dangers of gun violence," and "exists to spread dis-information, and knowingly puts guns into the hands of those who would harm and terrorize us." It asks the city to "take every reasonable step to limit those entities who do business with the City and County of San Francisco from doing business with this domestic terrorist organization."

In response, the NRA called the resolution a "ludicrous stunt," and now an attorney for the group, William A. Brewer III, says, "There can be no place in our society for this manner of behavior by government officials." He adds, speaking to the AP, that such a resolution is "an assault on all advocacy organizations across the country."

The Supervisors' resolution, which is non-binding, made national headlines and comes at a potentially politically pivotal moment for the NRA. Last week, on the same day that Stefani's resolution was passed, Walmart announced that it was ending the sale of handgun and assault-weapon ammunition, taking a further step than it has in the past to impact the proliferation of weapons in the U.S. The chain store's CEO, Doug McMillon, further wants to ask customers not to carry their weapons into the store β€” this was all in a memo to employees in response to the mass shooting that took place inside a Walmart location in El Paso, Texas.

As one of the biggest gun retailers in the country, Second Amendment advocates and the NRA reacted swiftly and loudly, suggesting a boycott on Walmart.

Stefani doubled down after hearing about the NRA lawsuit, telling the AP that it's "a desperate move by a very desperate organization." She added, "I truly believe their time is up."

Longtime NRA CEO Wayne LaPierre said in a statement, "This lawsuit comes with a message to those who attack the NRA: We will never stop fighting for our law-abiding members and their constitutional freedoms... We will always confront illegal and discriminatory practices against our organization and the millions of members we serve."

As Mother Jones reported last year, it's never been entirely clear how many members the NRA actually has β€” though LaPierre consistently likes to tout the figure "5 million." This is up from a dip 20 years ago to about 2.6 million, in the wake of incidents in Waco and Oklahoma City. Though audited circulation numbers for the NRA's magazines show that the actual circulation was about 3.4 million as of December 2017, less than a million more than that low point they claim in 1998.

Previously: SF Supervisors Declare NRA a Domestic Terrorist Organization, Hope Rest of Nation Will Follow