As President-elect Donald Trump prepares to move back into the White House, gun violence prevention advocates are bracing for him to keep his campaign promise to sign a nationwide “concealed carry reciprocity” law.

The move would allow gun owners with concealed carry permits to travel with their weapons to all 50 states, even those that do not honor out-of-state permit holders from doing so.

Twenty-nine states already allow some form of concealed carry reciprocity, including some that only honor concealed carry permits from out-of-state gun owners if their state reciprocates. Nine states — including California, Connecticut, Illinois, New Jersey and New York — and Washington D.C. do not honor concealed carry permits from other states.

Trump’s promise of nationwide reciprocity

The issue resurfaced over the weekend, when Trump’s son, Donald Trump Jr., posted a 2023 video on Instagram of his father vowing to sign legislation allowing concealed carry permit reciprocity nationwide.

“BOOM! My father just announced full concealed carry reciprocity! The 2nd Amendment will stay and remain protected,” Donald Trump Jr. wrote.

In the February 2023 video, President-elect Trump outlined a seven-point plan to “end crime and restore law and order,” including enacting nationwide concealed carry reciprocity.

“I will protect the right of self-defense everywhere it is under siege,” Trump said. “And I will sign concealed carry reciprocity. Your Second Amendment does not end at the state line.”

‘Law enforcement won’t know who has firearms’

Gun violence prevention groups are already gearing up for a new reciprocity battle.

“The biggest threat here is carrying a firearm across state lines without a permit. A piece that I really want to underscore is that law enforcement won’t know who has firearms,” Monisha Henley, senior vice president of government affairs for Everytown for Gun Safety, told ABC News.

At least 26 states, including Florida, Alabama, Kentucky, Louisiana and Georgia, have adopted permitless carry rules, meaning no gun permits are necessary to carry concealed weapons if the gun owner meets age requirements and is not prohibited from possessing firearms.

“Gutting state gun laws just makes it easier for dangerous people to carry a hidden weapon with no training, with no questions asked,” Henley said.

Henley noted that gun violence prevention groups successfully fought Trump’s efforts to loosen gun control laws during his first term in office.

Some gun violence prevention groups said they fear the potential passage of nationwide concealed carry reciprocity is just the first step the incoming Trump administration will take to roll back policies established by President Joe Biden to curb the national plague of gun violence.

During his victorious campaign, Trump and his running mate, Sen. JD Vance, voiced opposition to most of Biden’s executive orders to combat the scourge that the Johns Hopkins Center for Gun Violence Solutions found to be the leading cause of death in the United States for adolescents under the age of 19 for three straight years.

In May, Trump spoke at the NRA convention in Dallas and outlined some of the actions he intends to take in his second term.

“In my second term, we will roll back every Biden attack on the Second Amendment — the attacks are fast and furious — starting the minute that Crooked Joe shuffles his way out of the White House,” Trump said in the speech.

A day after the election, Kris Brown, president of the Brady Campaign to Prevent Gun Violence, said her group planning on “doubling down” in the fight to strengthen gun control laws.

“The movement to prevent gun violence has always been larger than one office, and we’ll continue to work with activists, survivors, community leaders and elected officials in states across the country to fight for progress that makes the whole country safer from gun violence,” Brown said in a statement.

Not the first time reciprocity has been proposed

During Trump’s first term in the Oval Office, the Republican-controlled House passed the Concealed Carry Reciprocity Act with a vote of 231 to 198. However, the Democrat-controlled Senate killed the legislation.

In his second term, Trump will have a Republican-controlled Senate. ABC News reported Wednesday that Republicans are projected to also retain control of the U.S. House of Representatives.

In January 2023, Rep. Richard Hudson, R-N.C., reintroduced concealed carry reciprocity legislation, saying, “The Second Amendment does not disappear when crossing an invisible state line.” The bill remains stalled in the House Committee on the Judiciary.

“The Concealed Carry Reciprocity Act protects law-abiding citizens’ right to conceal carry and travel freely between states without worrying about conflicting state codes or onerous civil suits,” Hudson said at the time he introduced the legislation. “I am especially proud to have such widespread and bipartisan support for this measure as I continue working to get this legislation over the finish line.”

Pat Harrigan, an Army veteran and Republican who won election last week to represent North Carolina’s 10th Congressional District, took to Instagram on Monday to voice support for nationwide reciprocity.

“President Trump is right: Just because we cross state lines does not mean that we should lose our Second Amendment rights,” Harrigan said in a video statement on Instagram. “If we want safer communities, we should pass national, 50-state concealed carry reciprocity and I’ll be right there next to President Trump.”