When residents of a gang-ridden neighborhood invited the mayor to a meeting to ask for help, it was gang members themselves who made the strongest argument: They sat in the back of the meeting room, carrying guns.
"These were 13-, 14-year-olds, wearing colors, with guns strapped to their hips," recalled Mayor Paul Johnson.The mayor got his second shock when he found out the teenagers weren't doing anything wrong.
Arizona is one of 25 states that allow people to carry firearms openly without a permit, and the "open carry" law has no age restrictions.
Johnson went on to push through an ordinance barring minors from carrying guns in the nation's ninth-largest city without their parents' permission.
The ordinance - part of national trend toward separating kids from their guns - has been imitated by at least one other Arizona community so far.
"It's good common sense," said the mayor, a Democrat. "If you tell someone he has to wait until he's 16 to get a driver's license, he can't vote, he can't buy a lottery ticket, but he can have a gun, something's wrong."
The National Rifle Association is threatening a court challenge to the ordinance.
Gun-control advocates are cheered by such measures.
"There's is a definite national trend, on the state and local level, to restrict firearms from people of all ages, but especially from children," said David Weaver, who works with state legislatures for Handgun Control Inc.
Legislation is pending in 26 states to hold adults responsible for allowing a minor access to a firearm, according to the NRA.
Supporters of such measures cite a report in June in the Journal of the American Medical Association that found gunshot wounds were the second-leading cause of death among high school-age Americans. One-third of high school students have access to handguns and 6 percent bring them to school, according to the study.
In the journal, Surgeon General Antonia Novello called violence in the United States a public health emergency.
"I think it is a national crisis," the Phoenix mayor said. "We've seen gangs for decades. But they used to get into fights with their fists and now they're carrying semiautomatic weapons."
After the Phoenix measure was approved unanimously by the City Council in May, neighboring Glendale passed a similar ban, and the City Council in suburban Scottsdale approved a resolution in favor of doing something similar.
Under the Phoenix measure, youngsters can be fined $50 and the weapon confiscated. Fewer than a dozen weapons have been seized since the ordinance took effect, and nobody has been fined, Sgt. Kevin Robinson said last week.
The NRA has offered to pay for any challenges to the ordinance based on the argument that the city lacks authority to be more restrictive than the state. The NRA's new president, Bob Corbin, is a former Arizona attorney general.
Under Arizona law, youngsters cannot buy guns and cannot be given guns without parents' permission. Carrying a gun is OK, as long as it is visible.
In the west Phoenix neighborhood where the mayor saw the armed teenagers, at least one resident said the ordinance doesn't go nearly far enough to keep guns away from kids.
"We need a law passed so kids can't get them at all," said Lupe Sisneros, 67. "It's the same as before when older kids bought the younger ones beer. It's all the same."