A federal judge has declared unconstitutional a provision in Maryland law regulating who can carry a handgun, effectively loosening the restrictions governing firearm possession on the state's streets.

In a 23-page memorandum opinion, made public Monday, U.S. District Court Judge Benson E. Legg said a state requirement forcing those applying for a gun-carry permit to show that they have a "good and substantial reason" to do so "impermissibly infringes the right to keep and bear arms," as guaranteed by the Second Amendment.

"A citizen may not be required to offer a 'good and substantial reason' why he should be permitted to exercise his rights," Legg wrote. "The right's existence is all the reason he needs."

The ruling was hailed alternately as a victory by gun enthusiasts, who saw it as a bolster to public safety, and as a dangerous precedent by gun opponents, who painted it as a return to the Wild West.

The Maryland attorney general's office vowed to appeal the ruling and request a stay of its implementation, while the plaintiff's lawyers have promised to fight to uphold it. Meanwhile, one Republican legislator is trying to change the law itself by erasing the requirement.

"I have a bill that does exactly what the court said we needed to do," said Del. Michael D. Smigiel Sr., who represents Caroline, Cecil, Kent and Queen Anne's counties. "It's there, it's been discussed, I have enough votes to get it out of committee. But for political reasons, it would never get out and have a chance to have a vote."

He's hopeful that the ruling will strengthen his efforts and garner bipartisan support for an often polarizing issue.

On one side are people like Chuck Ammann, a 67-year-old from Parkville who has owned a gun since he was 10. His father took him target shooting as a boy, and he still practices as an adult, but he also keeps guns for protection in his home. He's recently applied for a carry permit, because he tends to handle a lot of cash.

"Guns don't kill people, people kill people," Ammann said Monday, repeating an adage favored by gun proponents. In Maryland, "you don't let the good guys carry them," he said, "but every day you read in the paper that the bad guys have them and they do not have permits."

He applauded Legg's decision, which was based on a Baltimore County man's lawsuit that was supported by the Second Amendment Foundation, a national gun rights advocacy group, with some funding from Maryland Shall Issue, a local organization.

On the other side are groups such as the Brady Center to Prevent Gun Violence, which works to limit access to firearms.

"It's perfectly reasonable and prudent for Maryland to have law enforcement decide who has a demonstrated need to carry loaded guns in public. There's a whole other level of risk that the public is exposed to when civilians carry loaded guns on public parks, streets, in restaurants, what have you," said Jonathan Lowy, director of the Brady Center's Legal Action Project, which submitted a brief in the Maryland federal case, claiming that loosening the law would be detrimental.

"Maryland's law is completely reasonable, and to hold that the Constitution does not allow Maryland to make that reasonable decision, we think, is not supported by the case law," Lowy said. This decision "would be a very dangerous precedent to remain on the books. We hope and expect it to be reversed."

Maryland's gun laws require permits for people wishing to carry handguns outside the home. They're issued by the secretary of the state police to those who can show, among other things, that they aren't violent, convicted felons, alcoholics or drug addicts.

The secretary also was required, until now, to determine if the applicant "has good and substantial reason to wear, carry, or transport a handgun, such as a finding that the permit is necessary as a reasonable precaution against apprehended danger."

That's the provision that drew a challenge to the law.

On Christmas Eve of 2002, Raymond Woollard was at home at his Baltimore County farm with his extended family, when his son-in-law broke into the house, high on drugs and demanding his wife's car keys so he could buy more, according to court records. Woollard pointed a shotgun at the man, who wrestled it away, but was soon subdued by another family member, who trained a second gun on him. The man was held there for more than two hours, while the Woollards waited for police to arrive.

Woollard applied for a handgun carry permit in 2003, and was allowed to renew it in 2006, shortly after his son-in-law was released from prison, having been convicted of multiple offenses in separate instances.

But Woollard's 2009 renewal application was denied because he couldn't "produce evidence of a current threat," Legg's decision said, or a good and substantial reason to carry a weapon, such as carrying a lot of cash for business or working in a high-risk or regulated profession, like law enforcement and armored car personnel.