After a federal judge said New York could implement gun restrictions passed after the US supreme court struck down a century-old law, the state attorney general saluted “a victory in our efforts to protect New Yorkers”.

“Responsible gun control measures save lives and any attempts by the gun lobby to tear down New York’s sensible gun control laws will be met with fierce defense of the law,” Letitia James said on Wednesday night.

In June, in the aftermath of mass shootings at an elementary school in Uvalde, Texas and a supermarket in Buffalo, New York, the conservative-dominated US supreme court overturned a New York law passed in 1911.

The law said anyone wanting to carry a handgun in public had to prove “proper cause”.

Justice Clarence Thomas said the 111-year-old law was a violation of the second amendment right to bear arms and also the 14th amendment, which made second-amendment rights applicable to the states.

“Apart from a few late-19th-century outlier jurisdictions,” Thomas wrote, “American governments simply have not broadly prohibited the public carry of commonly used firearms for personal defense.”

In dissent, Stephen Breyer, a liberal, wrote: “In 2020, 45,222 Americans were killed by firearms. Since the start of this year there have been 277 reported mass shootings – an average of more than one per day.”

The same source, the Gun Violence Archive, now puts that total at 450.

Breyer wrote: “Gun violence has now surpassed motor vehicle crashes as the leading cause of death among children and adolescents. Many states have tried to address some of the dangers of gun violence … the court today severely burdens states’ efforts to do so.”

Joe Biden said: “I call on Americans across the country to make their voices heard on gun safety. Lives are on the line.”

Kathy Hochul, the governor of New York, said: “The supreme court is setting us backwards … This decision is not just reckless, it’s reprehensible.”

Hochul called the legislature back into session. It produced the Concealed Carry Improvement Act, or CCIA.

As defined by James, the CCIA “strengthens requirements for concealed carry permits, prohibits guns in sensitive locations, allows private businesses to ban guns on their premises, enhances safe storage requirements, requires social media review ahead of certain gun purchases, and requires background checks on all ammunition purchases to protect New Yorkers”.

The law was challenged by the Gun Owners of America and the Gun Owners Foundation. On Wednesday, the GOA said the CCIA “would essentially make all of NY a gun-free zone and infringes upon the rights of its citizens”.

Judge Glenn Suddaby, of the US district court in the northern district of New York, said the two gun groups lacked standing to bring the case.

But Suddaby also indicated support, describing “a strong sense of the safety that a licensed concealed handgun regularly provides, or would provide, to the many law-abiding responsible citizens in the state too powerless to physically defend themselves in public without a handgun”.

An appeal is likely. The CCIA went into effect on Thursday.

On Wednesday the mayor of New York City, Eric Adams, said: “The US supreme court’s … decision was the shot heard round the world that took dead aim at the safety of all New Yorkers.

“New York City will defend itself against this decision, and, beginning tomorrow, new eligibility requirements for concealed carry permit applicants and restrictions on the carrying of concealed weapons in ‘sensitive locations’, like Times Square, take effect.”

The new law has prompted a change in what New York City authorities officially consider to be Times Square. As the New York Times reported, the new boundaries extend far beyond the traffic-choked and neon-blitzed Midtown hub known to tourists worldwide but largely avoided by locals.

Under CCIA, the Times Square “gun free zone” will run “from Ninth to Sixth Avenues and from 53rd to 40th Streets and consists of about three dozen blocks”, the paper said.

One New Yorker interviewed by the Times dismissed the idea that the Port Authority Bus Terminal, on Eighth Avenue, could be considered part of Times Square, even in order to make it a gun-free zone.

“Nah,” Robert Govan, 62, told the city’s paper of record. “No way. Not going to happen.”