In the heart of Silicon Valley, voters approved a measure that both sides in the gun-control fight see as key to their causes.

Residents of Sunnyvale, a mid-sized city at the base of the San Francisco Bay, passed measure C on Tuesday in a 66 percent to 34 percent vote. The mayor, who pushed the measure in response to the Newtown, Conn. shootings, hopes its four gun-safety requirements will lay the groundwork for a renewed push for state and national gun-control action.

“This is not an issue that appears to be working from the top down,” says Sunnyvale Mayor Tony Spitaleri. “City by city, if we start doing something, it’ll give the base for legislators to stand on and take on these issues.”

Already, he said, citizens in neighboring Mountain View and Los Altos have reached out to learn more about the regulations to see if they can replicate them in their cities, he says. The measure has four requirements: gun owners must report loss or theft of a firearm within 48 hours of when they should reasonably have known it was missing; guns must be locked when not in use; large-capacity ammunition magazines will be prohibited, with some exceptions; and vendors will have to keep sales logs for two years.

But while proponents see the strict rules as laying the groundwork for broader gun limits, the National Rifle Association sees them as a great opportunity to challenge gun-control laws.

The prohibition on higher-capacity ammunition magazines is “the perfect vehicle for accelerated Supreme Court review,” says Chuck Michel, a civil rights attorney who represents the NRA on the West Coast.

Other states have imposed restrictions on magazines, but Sunnyvale’s new measure is unique, he says: “None of those go so far as the Sunnyvale ordinance does.” Even before the measure was passed, the NRA said it was seeking Sunnyvale residents to represent in challenging it.

Michel says he plans to file his challenge within days. When he does, Spitaleri says he and the city are ready.