One of the first gun bills introduced in the new Congress proposes to dramatically alter the way states regulate who can carry concealed firearms within their borders. Under the legislation filed by Congressman Richard Hudson, a North Carolina Republican, gun owners — including those from states no longer mandating training or permits for persons wishing to tote hidden pistols — could be cleared to carry in any public spaces across the country that allow guns.

Currently, every state allows for concealed carry. But many forbid out-of-state residents from carrying concealed weapons within their borders, or only recognize permits from select states. And some cities, like New York, have strict rules about who may obtain a license to carry, with the result that very few people do.

If Hudson’s bill passes, states that set high bars for concealed carry would be compelled to welcome gun-toting visitors from “any state that recognizes its residents’ right to concealed carry,” says a Hudson spokeswoman. That includes states with more relaxed requirements, or no requirements at all.

New York authorities, for instance, may be forced to allow a tourist from Mississippi — one of the 10 states that now authorizes permitless carry — to be armed while walking down Broadway, with his Mississippi ID the only permission he needs.

In seeking to establish national concealed carry reciprocity, Hudson’s legislation is in line with the top federal policy priority of the National Rifle Association. The underlying idea is not new — in fact, Hudson introduced a version of this bill in the last Congress, as well.

What is new is the inclusion of the permitless-carry language, which appears to be added in response to the momentum of the so-called “constitutional carry” movement, as proponents sometimes call it. Three states adopted permitless carry in 2016, and at least six are considering it as legislatures convene for their 2017 sessions, though that number is likely to grow.

For gun safety groups and law enforcement officials already opposed to national concealed carry reciprocity, the added recognition for permitless carriers is cause for extra concern.

“The lowest-common-denominator approach proposed by this bill would undermine the core principles of federalism, the traditional police powers of state governments, and the safety of law enforcement officers across the country,” New York Attorney General Eric Schneiderman told The Trace via email. “It’s absolutely unacceptable for the federal government to dictate that someone can carry a concealed, loaded gun within a state’s border, in violation of that state’s laws.”

The bill contains another provision that Hudson and other backers have not promoted publicly, even as they tout other aspects of the measure: It is designed to undo a federal law prohibiting guns at schools by declaring concealed carry holders are not subject to the ban. A spokeswoman for Hudson did not immediately respond to a request for comment about the guns-in-schools provision.

Hudson is a member of President-elect Donald Trump’s Second Amendment Coalition, which was formed during the late stages of the campaign to advise Trump on gun laws. In an appearance on Fox Business News, Hudson said that he is confident Congress will pass the legislation, and that Trump will sign it.

By Thursday, the bill had 77 co-sponsors, according to Tatum Gibson, a Hudson spokeswoman.

The NRA, which favors national concealed-carry reciprocity, spent more than $30 million to support Trump’s candidacy. The incoming president promised to deliver that change during his campaign.

On Thursday, the NRA endorsed the bill in a post on its website, without mentioning the permitless-carry or guns-in-schools provisions.

“Law-abiding citizens should be able to exercise their fundamental right to self-defense while traveling across state lines,” Christopher Cox, the gun group’s chief lobbyist, said in the post. “This is an extremely important issue to our members and we thank Congressman Hudson for leading the fight to protect our rights.”

The NRA did not return The Trace’s request for comment.

Constitutional, or permitless carry, allows gun owners to carry concealed weapons without receiving any training or permits from a state government. In just the last year, Idaho, Mississippi, Missouri, and West Virginia established or strengthened their permitless-carry laws, joining six other states — Alaska, Arizona, Kansas, Maine, Vermont, and Wyoming — that don’t require a license to carry a concealed weapon.

In states that do require a permit to carry, training standards vary greatly. As The Trace has reported, 24 states will issue permits without requiring an applicant to pull a trigger. Massachusetts, California, New York, New Jersey, Maryland, Delaware and Hawaii require applicants to show a specific need for obtaining a concealed-carry permit. But a reciprocity law would force these states to honor permits from states with few restrictions on obtaining one.

Even without the addition of the permitless-carry and guns-in-schools provisions, concealed-carry reciprocity is a highly polarizing concept that will likely become the most contested federal proposal related to guns this year.

The plan angers gun safety advocates who consider reciprocity to be efforts to spread some states’ lax gun laws across the country.

“This irresponsible proposal would create a race to the bottom by undermining one state’s good laws for carrying loaded, hidden guns in public with another state’s weaker laws,” said Robin Lloyd, the director of government affairs at Americans for Responsible Solutions, the group founded by former Congresswoman Gabby Giffords, who was shot in a 2011 assassination attempt.

According to his spokeswoman, Hudson will work with Senator John Cornyn, Republican of Texas, the majority whip, who has spearheaded previous efforts to pass concealed-carry reciprocity bills, on companion Senate legislation. It was not clear if Cornyn, whose office declined to comment, will offer identical or alternative legislation. Other House members may also offer competing proposals. In the last Congress, Hudson was one of three House Republicans who introduced reciprocity bills.

In a statement and summary of the bill, Hudson highlighted the provision extending permitless-carry rights outside of the borders of the states that allow it. He also backed language that allows gun owners to sue municipalities, police forces, and even individuals, that prohibits them from carrying a concealed gun. That provision may allow police officers to be sued personally for trying to check the validity of a claim by a gun holder that he or she has a right granted in another state, said Lindsay Nichols, a senior attorney at the Law Center to Prevent Gun Violence.

“It would have a severe chilling effect on officers simply trying to protect the public,” she said.

The bill also states that a person who “possesses or carries a concealed handgun” covered by the measure “shall not be subject to the prohibitions” of the Gun-Free School Zones Act of 1990. Trump promised during his campaign that he would get rid of gun-free zones, which are often mandated by state and local laws, on his “first day” in office. The NRA has also repeatedly urged ending prohibitions on guns at schools, but concealed-carry reciprocity advocates had not previously tied their proposals to the issue.

The concealed-carry push requires a difficult balancing act for Republicans, who generally advocate against federal encroachment on states’ power to set policy. Advocates of the bills deal with the contradiction, in part, by denying it. Hudson asserted on Fox Business that the bill would not impose new laws on states that don’t allow concealed carry. All 50 states, however, allow concealed carry for at least some people.

Backers of the legislation are also trying to manage tension between gun rights advocates who press for permitless carry at the state level but are trying to impose a uniform permitless-carry bill at the federal level. Hudson’s inclusion of “constitutional carry” is an effort to appeal to gun rights advocates eager to abolish all permitting.

“The language will ensure that those in constitutional-carry states receive the same reciprocity protections,” Gibson said in an email.

That measure and the school zone and damages provisions also help position Hudson’s proposal as more pro-gun than the competing plans that are expected to emerge.

A 1986 law, the Firearms Owners Protection Act, already allows gun owners with a permit to transport a weapon across state lines as long as it is locked in their trunk. For critics, that makes a reciprocity law not only dangerous, but unnecessary.

Nichols, the attorney for the Law Center Against Gun Violence, called it “a solution without a problem.”