WASHINGTON, DC (NEXSTAR) — While gun safety advocates and gun rights supporters rallied on the steps of the US Supreme Court Monday, the justices inside heard a case that could impact how states and cities can regulate firearms.

The case is the first major second amendment case to go before a high court in a decade and centers around a New York City gun law which regulated the transport of guns outside gun owners’ homes.

NYC repealed the ordinance when it was challenged in court. However, fun advocates took the case all the way to the US Supreme Court in hopes for a landmark ruling against state and city regulation of firearms.

Lawmakers in support of local regulations like Congressman Gerry Connolly (D-Va.) said, “We have a right to protect ourselves and our communities and the Supreme Court needs to hear from us.”

Senator Chris Murphy (D-Conn.) said the regulations make the cities safer.

Gun safety advocates of the Brady Campaign say gun regulations at the state and city level across the nation could possibly be struck down.

“Ultimately we want the court to uphold reasonable interpretations that ensure that things like background checks, extreme risk laws, that have now been enacted in 17 states and the District of Columbia and indeed an assault weapons ban can be upheld,” said Kris Brown, President of the Brady Campaign.

Paul Clement, who represented New York Rifle and Pistol Association argued back, “This is part and parcel of the kind of regulations that have no basis in text, history, or tradition and should not be upheld consistent with second amendment.”

A decision is expected by late June.