The resolution, which passed unanimously Tuesday night, claims the NRA "promotes extremist positions," "spreads propaganda" to deceive the American public about gun violence, incites gun owners to "acts of violence" and "has armed those individuals who would and have committed acts of terrorism."
NRA spokeswoman Amy Hunter called the resolution a "worthless and disgusting 'soundbite remedy' to the violence epidemic gripping our nation."
"This is a reckless assault on a law-abiding organization, its members, and the freedoms they all stand for," Hunter said in a statement to CNN.
The resolution is a largely symbolic one. It calls for the city and county to "take every reasonable step to limit" San Francisco's "financial and contractual relationships" with vendors who do business with the NRA. But the resolution does not, for example, carry the law enforcement implications of designation as a foreign terrorist organization.
Despite the rise in cases that law enforcement describes as domestic terror-related, there is no federal charge for "domestic terrorism." The US doesn't have a domestic terrorism law and no government agency designates domestic groups as being terrorist organizations. That means many cases the FBI calls domestic terror-related end up with a variety of charges for violations of laws related to guns or even other state charges.
The resolution was introduced in July after a shooting at the Gilroy Garlic Festival in California killed three people. The rebuke of the gun-rights organization, which vehemently opposes stricter gun legislation, passed on Tuesday in a meeting after supervisors returned from a legislative recess.
"This country is terrorized by gun violence, and we need to call the NRA what it is: a domestic terrorist organization," Catherine Stefani, the member of the 11-person board who proposed the resolution, said in a news release. "Nobody has done more to fan the flames of gun violence than the NRA."
"Every country on earth has video games, movies, and mental health issues, and yet only the U.S. has gun violence at elementary schools, at the movies, at Walmart," Stefani said. "The difference is guns. No other country has so many assault rifles on their streets."
The unanimous vote comes as a string of mass shootings has rocked the nation. In August, shootings in Dayton, Ohio, and El Paso, Texas, came hours apart and killed 31 people. On Saturday, at least seven people were killed in a mass shooting in West Texas.
After the shootings in Dayton and El Paso, President Donald Trump expressed openness to expanding background checks, but backed off under pressure from the gun lobby. NRA chief Wayne LaPierre told Trump in conversations after the shootings that the NRA doesn't think the calls for more restrictive gun measures in Washington match how his supporters in deep red areas feel about the issue, a person familiar with the conversations told CNN.
Trump has been unclear about what kinds of measures he would support, and Senate Majority Leader Mitch McConnell has continued to block gun measures passed by the Democratic-led House that enjoy bipartisan support on Capitol Hill. Among them are H.R. 8, which requires background checks on all firearms sales in the country; and H.R. 112, which closes a loophole in current law that enables some firearms to be transferred by license gun dealers before required background checks have been completed.
McConnell has said he will not put any gun control measures on the floor without assurances from Trump that he will sign them.
The move also comes amid a leadership exodus and other signs of turmoil at the NRA. The group is facing intense scrutiny of its finances, is locked in a legal battle with its former ad agency and is dealing with mounting criticism in the wake of the recent mass shootings. In April, the NRA's then-President Oliver North was ousted following a dispute with LaPierre.