PORTLAND — Police chiefs from several of Maine’s largest cities joined activists Wednesday to denounce a proposal to scrap the state’s concealed-carry permitting process for a more relaxed law that would allow nearly anyone to carry a hidden handgun.

“If this passes, I’m certain a tragedy will occur,” said Larry Gilbert, a former Lewiston mayor and police chief, during a news conference at the Portland Police Department.

Law enforcement officers stressed that because of Maine’s porous background check laws, the concealed carry permitting process is often the only opportunity they have to keep bad actors from walking around with loaded weapons.

Portland Police Chief Michael Sauschuck said that in 2013, his city issued 159 concealed carry permits, but denied 23 others. Those that were denied were because of the applicant’s history of domestic violence, drug abuse or mental health issues, he said.

“Not only should they be denied a concealed carry permit, but they shouldn’t have a firearm at all,” Sauschuck said. “Without this process, we wouldn’t be aware of the situation.”

That’s because Maine currently only requires criminal and mental health background checks for those who purchase guns from licensed firearms dealers. If one buys a gun from a private vendor online, or through Uncle Henry’s or even at a yard sale, nobody is required to verify that the buyer is legally permitted to own the gun.

Law enforcement estimates that 40 percent of all firearm purchases are made without any background check. Sauschuck said the new law would make things worse.

“If this bill passed, you could buy that weapon without a background check and immediately tuck it into your shirt and walk down the street. That sends a bad message, particularly to drug dealers,” he said. “We don’t want to make our communities a more marketable location to drug dealers or anyone else that’s here to do a criminal act.”

Gilbert and Sauschuck were joined by officers from police departments in South Portland, Scarborough, Westbrook, Windham, Gorham and Yarmouth, as well as the Cumberland County Sheriff’s Office. The Maine Chiefs of Police and Maine Sheriffs Association also oppose the bill.

While law enforcement and gun control advocates have pilloried the bill, it has the support of a majority of the Legislature. The bill’s sponsor, Sen. Eric Brakey, R-Auburn, has argued that the bill does not allow anyone to own a firearm who is currently prohibited. Because Maine law already permits the open carry of handguns, he said, the bill should be noncontroversial.

“The current system is not a system that makes you jump through hoops to carry a handgun,” Brakey said. “It’s a system that makes you jump through legal hoops to wear a jacket.”

Opponents who gathered Wednesday in Portland dismissed that argument as a glib oversimplification. Tom Franklin of Maine Citizens Against Handgun Violence said there’s a big difference between someone openly carrying a weapon and someone hiding it, and that the state has an interest in ensuring that those who hide guns can be trusted.

The rationale behind Maine’s concealed carry permitting law is obvious, he said.

“Some owners of guns are dangerously unstable, not many, but still far too many,” he said. “Concealing a gun makes it a whole lot easier to walk into a bank, a convenience store, a movie theater or a school and commit a crime. It’s just as obvious that we should be concerned about who is allowed to carry a gun into these places.”

Just five states, including Vermont, have universal concealed carry — called “constitutional carry” by supporters.

Maine’s concealed carry permitting law has been around since 1908. In its current form, it requires applicants to fill out a form, pay a fee, take a handgun safety course and pass a background check for “good moral character,” which includes a review of police and other public records drawn from the past five years.

A public hearing on Brakey’s bill is scheduled for 1 p.m. Wednesday.