There are now 22 states disputing the constitutionality of New York state’s ban on semi-automatic weapons passed in 2013.

22 States Have Signed on to Oppose New Yorks Gun Ban

Gun-rights activists hold signs during a Second Amendment rally on Tuesday, June 11, 2013, in Albany, N.Y. (AP/Mike Groll)

South Dakota on Tuesday became the latest state to sign onto a “friend of the court” brief challenging the constitutionality of the ban in the 2nd U.S. Circuit Court of Appeals. Wyoming and Montana joined the brief on Monday.

While nearly half of all U.S. states have joined in opposition to New York’s law already, the top plaintiff in the case expects more states to join.

“We have a lot of attorneys general throughout the states and would have more, except some believed they should not be involved with the Second Circuit,” New York State Rifle and Pistol Association President Tom King told TheBlaze. “We believe we will have 44 to 45 states by the time this reaches the Supreme Court.”

The New York Secure Ammunition and Firearms Enforcement Act of 2013, better known as the NY SAFE Act, bans possession of semi-automatic weapons that opponents call “assault weapons;” bans high-capacity magazines; expands background checks for gun buyers and gun dealers; and bans the Internet sale of guns, among other restrictions.

A federal district judge in December upheld most of the law, rejecting arguments that it violates the Second Amendment because the law addressed the “important governmental interest” of public safety. The law was adopted following the Newtown elementary school massacre.

The states challenging the New York law in the “friend of the court” brief are: Alabama, Alaska, Arizona, Arkansas, Florida, Georgia, Idaho, Kansas, Kentucky, Louisiana, Michigan, Missouri, Montana, Nebraska, North Dakota, Oklahoma, South Carolina, South Dakota, Texas, Utah, West Virginia and Wyoming.

A party does not have to have standing to file an amicus brief. The states are asserting their concerns that if a federal court upholds the New York state law, that what they deem an unconstitutional law could be passed in other states.

“While the ban only applies to New York at this time, the federal court’s upholding of the gun ban sets a concerning precedent interpreting limitations on Second Amendment rights of all law-abiding citizens including here in South Dakota,” South Dakota Attorney General Marty J. Jackley said in a statement. “An outright ban on semi-automatic weapons used for self-defense and hunting purposes violates the Second Amendment.”

Three of those states – Arkansas, Kentucky and Missouri — have Democratic attorneys general, another reason King if confident of even broader bipartisan support.

“Anywhere outside of New York, the Second Amendment is not a partisan issue,” King said. “We expect to be successful. It may take the Supreme Court for it to be successful.”

A representative for New York Gov. Andrew Cuomo did not respond to phone and email inquiries from TheBlaze Thursday.

In one of Cuomo’s more famous impassioned speeches arguing in favor of the weapons ban, Cuomo said in January 2013: “I say to you forget the extremists. It’s simple — no one hunts with an assault rifle. No one needs 10 bullets to kill a deer and too many people have died already.”

Wyoming Gov. Matt Mead asserted his state was entering the lawsuit to protect the civil liberties of all people.

“This is another case where one state’s gun laws could have a negative impact on Second Amendment rights nationally and in Wyoming,” Mead said in a statement. “These rights are fundamental to the people and critical to our way of life. I will continue to protect our Second Amendment rights.”

The amicus brief says New York’s ban of semi-automatic firearms, including in the home, constitutes a categorical ban on possessing certain firearms that are commonly owned for self-defense and are among the “arms” protected by the Second Amendment. Because New York’s ban on semi-automatic weapons burdens the core of Second Amendment rights, the states argue that the SAFE Act is unconstitutional. The amicus brief further argues that New York’s ban of these firearms has little effect on gun violence and is not the least restrictive means to serve the state’s interests in public safety and crime prevention.

“Semi-automatic firearms are perhaps the most commonly used firearm for self-defense,” Montana Attorney General Tim Fox said in a statement. “Excluding an entire class of firearms from law abiding citizens limits their ability to lawfully protect themselves, their families, and their homes. It would also impact law-abiding sportsmen and shooting enthusiasts, because semi-automatic rifles, handguns, and shotguns would not be available for their use either.”