GREENLAND, N.H. — This is the pitiful state of the American town hall meeting: Even the people who invented it can’t make it work anymore.

“ORDAH!” In the Greenland town hall, a man was yelling at Rep. Frank Guinta, R-N.H., for splurging on glossy paper for his office mailings, while another constituent was trying to interrupt, shouting aimlessly: “Our nation is about to go into crisis.”

“ORDAH!” somebody yelled again. But there was no order.

In this same town, the residents of Greenland gather every spring to settle their differences in a civil, orderly, traditional New England town meeting. This month, Guinta couldn’t even get them to shut up long enough to finish a thought.

“I want everyone who’s here to have an opportunity to give their opinion,” said Guinta, a freshman legislator with the look of a crestfallen teddy bear. “So let’s just try to respect everyone’s time, um …”

He was interrupted.

“So let’s go back to the costs on the glossy!” the first yeller demanded.

Why is Congress so partisan and divisive? Why is American politics so confrontational and contentious? The answer may have something to do with the broken state of the national town hall meeting, a staple of congressman-voter interaction, and of American democracy more generally.

So what happened to the town hall?

Part of the problem is the altered political landscape; it’s not just that talk radio has made screaming popular. Legislators say that voters are now more interested in national issues — on which a single lawmaker has little power to effect change — than in local ones, for which the problem may be easier to resolve. Which means fewer people arrive at meetings with a reason to listen.

But also, the tools of citizenship and activism have changed with the advent of YouTube and new, more aggressive strategies from activist groups on both sides. Somehow, an event that was once all about listening has become all about shouting. It now counts as a defeat if one’s opponent is allowed to make a point in peace.

One potential danger is that congressmen take away the message that America is just as estranged and divided as their town hall meetings.

There will be about 500 congressional town hall meetings during this summer’s recess from Capitol Hill, involving 153 of the 535 members of Congress, according to a database maintained by Knowlegis. That’s down from 659 meetings in the summer of 2009, when tea party groups used the gatherings to target Democrats for their support of a health-care overhaul.

This summer, liberal groups have tried to do to Republicans what was done to them two years ago. They have targeted GOP town halls to demand higher taxes on the rich and on corporations, and to push for new jobs in infrastructure and clean energy. Already, there are similar results: Freshman Rep. Lou Barletta, R-Pa., who blasted his opponent for not holding town halls last year, has suspended his own meetings after disruptions by liberals.

“What we say is, ‘Get there early, bring signs and be visible, and ask tough questions,’ ” said Justin Ruben, executive director of the liberal group, which Barletta blamed. MoveOn encourages people to be civil, Ruben says, but the GOP needs to understand the high level of voter frustration. “The best thing for our democracy right now is for Republicans to get an earful.”

The new basic unit of political discourse at many town halls this summer is not the question or the comment, but the earful.

Even legislators who say they enjoy a spirited give-and-take have had trouble getting the quiet required for such an exchange.

“Let’s please observe the fundamentals of a town hall meeting, which is respect for our fellow citizens’ views. All right? Can we agree to that?”

This is Sen. John McCain, R-Ariz., talking at the beginning of a town hall in Tucson this month. McCain is known for his willingness to engage an audience, but he acknowledged privately that he had noticed something different in the latest meetings, something angrier.

In this case, the crowd applauded his plea for civility. And then people listened quietly . . . for about eight minutes.

“Sir, you’ve got to let me finish, and then I’ll let you talk,” McCain said, still holding his notecards, talking to a man hectoring him about corporate tax rates. The man didn’t stop. “Sir, I am finishing my opening remarks, and then I will let you be the first to speak, if you will let me finish my remarks.”

Of course, some of the changes in the town hall are by design.

In May 2009, Rep. Jim Himes, D-Conn., called a town hall meeting in Fairfield. He thought it was to discuss preparing “southwest Connecticut to be a leader in the 21st-century economy.”

But Bob MacGuffie, a conservative activist angry about President Barack Obama’s stimulus spending bill, which was passed by the Democratic Congress, had another idea.

“We’re not going to let him get away with the usual staged presentation,” MacGuffie says now, remembering. “So when he started saying stuff that wasn’t true, we called him on it. We yelled back.”

Afterward, having seen how Himes was rattled, MacGuffie wrote up a memo that inspired conservative groups to stage angry confrontations with Democratic members of Congress that came to define congressional town halls of 2009. The memo was a set of stage directions, a user’s manual for using somebody else’s town hall meeting to create your own political theater.

“Spread out in the hall and try to be in the front half. The objective is to put the Rep on the defensive with your questions and follow-up,” MacGuffie’s memo said. ” . . . You need to rock-the-boat early in the Rep’s presentation.” It advised people to yell out even before the legislator finished an opening statement.

These ideas are deeply embedded into a new concept of what a congressional town hall meeting is supposed to be. Even in New Hampshire, where people should know better.

The man who shouted at Guinta about the glossy paper, for instance, was Mark Vallone, 57, of Epping, N.H. He has been going to town hall meetings for years and has always behaved. So why did he interrupt Guinta on this day?

Because, Vallone said, he knew it would work. He knew from watching tea party activists use the same tactics against the Democrat whom Guinta defeated, Rep. Carol Shea-Porter.

“It would get his attention,” Vallone said afterward, standing outside the town hall. “The next town hall, I’ll be there.”

As he spoke, the man who had tried to interrupt him inside the hall was loudly insulting Vallone’s wife on the sidewalk, yelling about her political views.

For politicians in 2011, these changes mean learning the skills that rookie comedians discover on open-mic nights. Hit the hecklers early, and don’t let them see they are getting under your skin.

This week in Yorktown, Va., Rep. Rob Wittman, R-Va., clamped down on one of the first people who shouted out.

“I’m going to make sure that I rule the meeting,” said Wittman, walking in the man’s direction. “I’d appreciate it if you would respect that.”

A few minutes later someone in the audience said Wittman was acting like a “terrorist.” The legislator tried to modulate his voice as he responded, because his emotion might only feed the crowd’s.

“I take umbrage with your assertion that I’m a terrorist,” Wittman said. The voice was flat. Only the slightly elevated volume gave Wittman’s anger away. “I am not.”

Staff writer Rosalind S. Helderman and staff researcher Lucy Shackleford contributed to this report.