Few people are more aware of the human toll taken by our expansive view of the Second Amendment than the mayors of the nation's big cities. But so far, that awareness hasn't translated into effective gun control activism.

Indeed, the recent history of big cities' attempts at gun control is a litany of legislative and courtroom failures and futility that have only served to strengthen gun rights. Washington and Chicago attempted to ban handguns within their jurisdictions, but the Supreme Court rejected both ill-conceived laws within the last four years. In the Chicago case, the court explicitly confirmed for the first time that the individual right to keep and bear arms applies to the states.

Philadelphia's legislative gun control gambits have been far less consequential, if only because they are plainly in violation of state law. That didn't stop Mayor Nutter from signing a package of gun control ordinances in 2008, but it has stopped the city's prosecutors from enforcing the laws.

Urban problem

How about the political pulpit, then? Surely the mayors of the cities most affected by gun violence, including Philadelphia, would make for effective gun control ambassadors. Right?

Not so much. When big-city mayors make themselves the public faces of gun control - think Michael Bloomberg, Chicago's Rahm Emanuel, and potentially Nutter - it appears only to make it easier for suburban and rural residents to dismiss gun violence as an urban problem that need not concern them.

After all, the national political momentum for increased gun control - inasmuch as it exists - picks up only after suburban massacres like the one last month in Newtown, Conn. Nationwide public opinion on guns is unmoved by the daily violence that afflicts Philadelphia and other big cities.

But there might be a third option for mayors, one that Nutter outlined this week. It seeks to use the financial clout of public pension funds to encourage gun and ammunition manufacturers - and, critically, the retail outlets that sell their wares - to throw their support behind gun control measures.

This is an untested idea, and it's not at all clear that it will work. But it seems to me to have a better chance than clearly illegal legislation or another speech about inner-city violence from another mayor trying to reach suburban and rural Americans who just aren't listening.

Even in its sadly depleted state, Philadelphia's pension fund is worth about $4.2 billion. New York City's has about $126 billion under management. Chicago's has about $13.5 billion. You get the picture: This is serious money, and it won't do companies any good to lose big pension funds as investors.

Now, for manufacturers of semiautomatic weapons, Nutter's proposal - along with similar ones in other cities - is a laugher. They'll seek investors elsewhere.

But what about retailers like Walmart, the nation's largest firearms seller? Would Walmart voluntarily stop selling semiautomatic rifles in the face of massive sell-offs of its stock by pension funds?

Nutter is calling his initiative the "Sandy Hook Principles." No doubt his heart aches for the victims of that massacre. But he could just as easily have called it the "22d Police District Principles," after the North Philadelphia district where 46 people were murdered and 188 were shot in 2011.

Some surely think it's crass for big-city mayors to use the opportunity created by a mass shooting of innocent kids in the suburbs to push for reforms that would likely do more to curb urban street violence. But what would you do if you were a mayor who believes easy access to guns is a central reason for the violence racking your city?

True, some public officials use the Second Amendment as a too-easy excuse for violence in their cities. There was a sense in the waning days of the Street administration that the mayor and police commissioner had thrown up their hands, partly because of the easy availability of guns.

Dispiriting trend

Nutter hasn't done that. Yes, he sees guns as part of the problem. But he has also changed up policing strategy and lectured parents ad nauseam about their role in preventing youth violence.

For a while there, something was working. Shootings and homicides both dropped sharply during Nutter's first two years in office. But the decline has stalled, and homicides have increased slightly in each of the last three years.

Would widespread adoption of Nutter's Sandy Hook Principles by pension funds reverse that dispiriting trend? I hope we get the chance to find out.

Patrick Kerkstra is a freelance journalist and former Inquirer staff writer. He can be reached at Patrick@PatrickKerkstra.com, or on Twitter at @pkerkstra.