Acting Attorney General John Hoffman did the right thing when he put a quick stop to a disturbing activity by undercover State Police troopers - taking pictures of protesters at Gov. Chris Christie's town hall rallies.

Hoffman was reacting to outrage - and had some of his own - over a plainclothes trooper who photographed protesters who disrupted and were escorted from a town hall meeting March 18 in South River, Middlesex County.

Senate Majority Leader Loretta Weinberg, D-Bergen, said the incident "comes across as an act of political intimidation." First Amendment experts said the practice could have a chilling effect on people exercising their right to free speech. We agree.

And the incident struck an unusual sour note for a governor who has been the most media-savvy chief executive New Jersey has ever seen. Christie is comfortable in front of the camera, good with an ad lib, and his Statehouse press machine pumps out positive releases and videos at a furious clip. He's also pretty handy at dealing with hecklers.

A Christie spokesman said the governor was unaware that protesters were being photographed. Let's hope that's true.

Christie's town hall meetings - he has held more than 100 of them all over the state - are a particularly effective public relations innovation. The highly orchestrated events, usually held in safe Republican strongholds, allow the governor to roll up his shirtsleeves and take soft questions from a supportive audience as he puts his spin on the issues of the day.

Lately, however, since members of Christie's staff have been embroiled in a controversy over lane closures at the George Washington Bridge and the governor's approval rating has fallen, the town halls have become a bit more raucous. At two recent meetings, protesters interrupted and heckled the governor.

On March 18, a dozen protesters shouted questions about the bridge scandal and problems with the distribution of Hurricane Sandy aid and chanted "New Jersey deserves better."

Christie had warned his audience to expect hecklers to disrupt the meeting, saying the protesters were pawns of a public-employee union. "They are recruited by the people we have been standing up against for the last four years," he said. Christie waited patiently as the protesters were escorted out by state troopers.

But it's one thing for the governor to be dismissive of critics. It's quite another thing to put them under surveillance.

A State Police spokesman said the pictures taken last Tuesday will be destroyed. And Hoffman's directive, that State Police will no longer photograph people at town halls "for security or any other purpose," should put an end to this practice.

The next step, which Hoffman says is under way, is to find out who ordered the surveillance in the first place - and what they intended to do with those pictures.