"You'd think, with something as significant and lethal as a gun, that any law-abiding citizen would want to report a dangerous device that may end up in the hands of a person who shouldn't have a weapon or sold to someone who can't legally possess it," said Nutter.
The four cities were among 30 that enacted lost-and-stolen gun reporting requirements after similar statewide legislation failed in 2008.
The mayors, along with Pittsburgh City Councilman Bruce Kraus - who authored that city's lost-and-stolen ordinance and spoke on behalf of Mayor Luke Ravenstahl - emphasized that they support citizens' Second Amendment right to bear arms, but believe the pending bills are based on unfounded fears of city governments' taking away such rights.
That concern was voiced Tuesday when backers of the bills sat down Tuesday with the visiting mayors, according to people who were present. One legislator made the "slippery slope" argument - that a relatively modest gun-control measure could lead to greater restrictions on law-abiding gun owners. Nutter retorted: "Slippery slopes don't kill people."
He rattled off Philadelphia's 2011 statistics: 316 homicides, 85 percent with guns, all of them illegal.
The proposed legislation also would allow nonresidents and gun-rights groups such as the National Rifle Association to challenge local laws in court and force municipalities to pay double their actual damages, plus attorney fees and costs, even if the municipality repealed its ordinance while such a suit is pending.
The House version, House Bill 1523, has received preliminary approval but has not been scheduled for a final vote. The Senate bill, Senate Bill 1438, is still in committee.
Nutter predicted that the flood of resulting lawsuits would bankrupt or severely harm cities that are already cash-strapped. "It's a waste of taxpayer money to defend ourselves when we are trying to defend our people," he said. "It's a mindless debate."
Ordinances in Pittsburgh and Philadelphia have thus far survived court challenges. In several cases, state judges ruled that various plaintiffs, including the NRA, did not have standing in court to sue.
Supporters of the bills now pending in Harrisburg say the cities' ordinances violate state gun laws' "preemption" language, which bars localities from imposing their own regulations on lawful gun ownership.
"My main purpose is to have one set of firearms laws across the state," said Sen. Rich Alloway (R., Franklin), prime sponsor of the Senate measure. "With multiple laws, you have people with no criminal intent breaking laws they didn't know existed."
Critics also say the municipalities that have enacted the lost-and-stolen reporting ordinances have not enforced them.
Nutter and the other mayors said their intent is less about making single arrests for failure to report guns lost or stolen, and more about gaining enough momentum to one day prevail in the legislature, as they did by passing local smoking and texting-while-driving bans, which eventually became state law.
The mayors also contended that the legislature has put them in a kind of vise grip: Lawmakers won't pass a statewide lost-and-stolen gun reporting law, and now they want to prevent cities from acting on their own.
"We can't protect the people we were elected to protect," said Mayor John Linder of Chester, where the city controller, Edith Blackwell, is recovering from a wound she received from a stray bullet while standing outside a gas station in broad daylight.
"Ordinances set an example for what the people behind us should do on a state basis," said Nutter, gesturing to the Capitol building behind him. "Now the problem is being enforced on the local level."
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