There's an old rule in journalism that three of anything equals a trend story. So allow me to suggest, using the examples below, that commonsense gun-law proponents are gaining ground in this scared state.

Last spring, I wrote about Pennsylvania towns' enacting gun measures in defiance of the powerful National Rifle Association and wimpy state legislature. In a matter of months, nine cities - including Lancaster, Pittsburgh, and Erie - attacked illegal gun trafficking by making it a crime not to report a weapon that's been lost or stolen.

Last week, after unrelenting protests by the faith-based group Heeding God's Call, the U.S. Attorney's Office filed charges accusing Colosimo's Gun Center of selling to straw buyers. In days, Colosimo's owner pleaded guilty and Philadelphia's most notorious gun shop was out of business.

Now, the NRA is lashing out at the surging ranks of a group called Mayors Against Illegal Guns.

The mayors' group aims to honor the right to bear arms while "fighting to keep criminals from possessing guns illegally." The NRA suspects the mayors really want to gut the Second Amendment.

So earlier this month, the gun lobby launched a mass mailing accusing the mayors of harboring a more radical agenda. Some politicians buckled, but most decried the "smear campaign" to scare them into silence.

Vineland, N.J., Mayor Robert Romano - a 34-year police veteran and proud gun owner - was so steamed he held a news conference and posed with his weapons.

"The NRA is not being truthful," Romano told me. "They view this organization as a threat. And now they want to dismantle us."

Strength in numbers

Of the 450 members of Mayors Against Illegal Guns (www.mayorsagainstillegalguns.org), 125 are from Pennsylvania. Michael Nutter stands up for the cause. So does Joe Cisco, longtime mayor of Ellport Borough, population 1,700.

"Please don't take this the wrong way," Cisco told me, "but we don't want our small community to end up like Philadelphia."

Cisco, a Western Pennsylvania hunter and retired steel-mill worker, saw the group as a way to keep big-city violence at bay.

"Then I got this postcard saying I'd joined an elite antigun group," a still-disgusted Cisco said. "It just slandered us up and down."

NRA members all over Ellport received the same postcard and dutifully followed instructions to harass Cisco. The harshest threats were anonymous; those who left a name got a call back offering a personal visit from the mayor to "tell my side of the story."

NRA spokeswoman Alexa Fritts would not say how many postcards went out, but she insisted the "education campaign" was not meant to intimidate.

Still, Fritts said that survival-minded mayors did have cause for concern: "They know it's not smart to be on the wrong side of the gun issue."

Who's crying now?

A funny thing happened amid all the fearmongering: Fourteen Pennsylvania mayors left the group, but 25 joined in spite of the pressure.

Akron Borough's John McBeth quit in disgust, even though he's running unopposed in his Lancaster County town of 4,000.

"I don't need the hassle," he said.

With time to think about the "smear campaign," McBeth wonders if the one on the wrong side of the gun issue isn't the NRA.

He feels momentum building for municipal lost-and-stolen laws. Eventually, we agree, leery legislators will have enough political cover to pass a state law.

And if that happens, could a one-gun-a-month law be next? Who knows, the NRA's treacherous tactics could fuel a legislative trend.

"I had about eight NRA members call me. I had 60 people tell me they wished I would have stayed in or that they do not feel favorably about the NRA," McBeth noted. "If I was simply doing the popular thing, I would have stayed in."

at 215-854-4670 or myant@phillynews.com.

Read her recent work at http://go.philly.com/yantkinney.