Manhattan District Attorney Cy Vance
Manhattan District Attorney Cy Vance walks outside New York Supreme Court to a press conference after former International Monetary Fund leader Dominique Strauss-Kahn was released on his own recognizance during a hearing on July 1, 2011. Photo by Mario Tama/Getty Images

New York's turnaround on violent crime has improved the lives of all New Yorkers. In 1990, there were more than 2,000 murders in our city. Last year, there were 335. Our safe streets have subsequently enabled an economic resurgence that has proven especially beneficial to real estate developers like President Donald J. Trump. I'm proud to say that New York remains the safest big city in the nation, at least according to the Economist's Safe Cities Index.

But this progress could come to a screeching halt if the Concealed Carry Reciprocity Act, known as CCRA, passes Congress. Every state has had the right to craft its own firearms licensing laws. In New York, we have crafted our laws to consider unique factors like our state's population density, culture and history. The CCRA would override our state's restrictive concealed-weapons permitting system and force New York to honor concealed-carry firearms privileges issued in other states, even though many other states have much looser standards. Simply put, this means that the gun laws of Arkansas, for example, could be forced upon New York by federal mandate. I can only imagine how angry citizens of Arkansas would be if Washington politicians forced them to follow laws from New York.

Consider this: Eleven states grant concealed-carry privileges to individuals who have not undergone any safety training. Twenty states grant permits to people who have been convicted of violent crimes. And 12 states do not require any kind of permit or license to carry a concealed firearm. The CCRA would make it legal for someone to carry that concealed, loaded firearm into New York or anyplace else, regardless of local law.

Public safety is like oxygen. We don't always notice when we have it, but if it went away, we'd realize quite quickly. Without security and stability, tourists wouldn't visit. Developers wouldn't have the confidence to invest. Businesses would lose out on top talent, and their customers would flee.

Public safety also means not having to worry when our children ride the bus to school or take the subway to visit a friend on a Friday night. Public safety is the reason we feel comfortable living, working and raising families in places like Manhattan. As the No. 1 tourism destination in the United States, my city receives more than 46 million adult visitors from other states each year, and 6.5 per of American adults have a concealed handgun permit. Passage of CCRA could unleash countless new concealed weapons on the streets of New York. That could mean more shootings, more victims and more tragedies in America's safest big city.

No one will bear the burden of those tragedies more heavily than our police. Under the CCRA, cops would have to patrol our streets surrounded by hidden, loaded guns. They would have no way to confirm whether an out-of-state permit is legitimate and no database to check on the status of those permits. And because many states don't even require permits to carry, the NYPD would have to take armed individuals at their word. So police officers are against this bill. Prosecutors, like me, are against this bill. Who would actually be for this bill? I can offer one answer: ISIS. According to George Washington University's Extremism Tracker, New York is the top ISIS terror target in America. Meanwhile, ISIS is increasingly recruiting radicalized attackers to murder as many people as possible, using any means available.

Let's not kid ourselves: ISIS is following the gun debate. Look no further than Rumiyah, its official magazine and how-to guide for terror. In its May 2017 issue, under a section titled "Just Terror Tactics," ISIS specifically told aspiring terrorists how to exploit America's lax gun laws to commit mass shootings on our soil:

"In most US states, anything from a single-shot shotgun all the way up to a semi-automatic AR-15 rifle can be purchased at showrooms or through online sales — by way of private dealers — with no background checks, and without requiring an ID or a gun license."

The CCRA is a gift to these terrorists. A person on a watch list could purchase multiple handguns at a gun show, take those guns into Manhattan and carry them, fully loaded, into Times Square. It wouldn't be a crime until they started shooting. Despite this astounding possibility, the CCRA already has more than 200 sponsors in the House of Representatives, and the National Rifle Association has called passing the bill its No. 1 priority. The gun lobby is making it politically dangerous to oppose this bill. We have to make clear that what's in this bill is even scarier.

Republican members of Congress have long championed the rights of states to establish their own laws that reflect local needs and concerns over national legislation — particularly when it comes to public safety. The CCRA tramples on those rights. If for no other reason, Congress should reject this unprecedented exercise of federal power.

If they do not, the President should exercise his veto authority. Trump is a New Yorker — perhaps the most famous one we have. Presumably, he understands that guns in the hands of criminals and terrorists would be bad for New York. He also states frequently that he is a strong supporter of police.

If the CCRA passes Congress, the President should align himself with law enforcement — including, among others, the International Association of Chiefs of Police, the Major City Chiefs Association and Prosecutors Against Gun Violence — and veto this dangerous legislation. The public safety we take for granted in cities like New York depends on defeating this bill.

I know that there has been significant reporting on previous contributions to my campaigns in recent weeks. Campaign contributions have never, and will never, have any impact on my work or the work of the professionals in the DA's office. My focus will always be on issues that make for a more just, fair and safe Manhattan, including ensuring terrible bills like CCRA are defeated.

Cyrus Vance is running for re-election as Manhattan DA.

Parts of this op-ed were previously published on CNN.