BURLINGTON, Vt. – Inside a plain-enough country club restaurant nestled in this Champlain Valley college town, the latest crimes against the laws of social etiquette are being committed during the Monday lunch hour.

For at one table a 56-year-old man dressed in white golf shirt, zip-up fleece and rumpled khakis is hunched over a hot cup of beef barley soup, taking slurps with such alarming speed you wonder whether he should wear a seat belt.

This is not his only infraction. His elbows are resting right there on the table. And before food ever came, fork, spoon and knife were all crowded on one side of his plate, huddled over there like passengers on the port side of a starboard-listing ship.

What on earth would Emily Post say?

Well, ask the soup slurper: He is Peter Post, great-grandson of the woman who, 46 years after her death, still reigns in the cultural consciousness as the unchallenged arbiter of thank-you notes, wedding receiving lines and how to fold a formal napkin.

And along with various other descendants and in-laws of the matriarch, he presides over a booming empire of etiquette – books, magazine columns, corporate seminars, podcasts, a torrent of media interviews, all in the Emily Post name.

All the while the family is trying to shake the traditional image of etiquette – a Byzantine set of because-she-said-so strictures no more relevant to daily life than the rules of Olympic curling.

What the Post family wants – as you fork over $19.95 for its latest book or notch another hit on its Web site – is for you to think of etiquette as a way to bring a little respect and consideration into an increasingly square-shouldered world.

So never mind that Peter Post is hurtling through his soup course. He is the law in these parts.

The nucleus of the Post dynasty is a place called the Emily Post Institute, a name that evokes a vast cubicle farm of manners police, or perhaps a 19th-century sanitarium.

It is in fact a couple of multi-room offices with soaring ceilings and sunlight streaming in through huge windows, in a red-brick former schoolhouse on a quiet street in Burlington.

The people who work here are constantly redefining etiquette, responding to changing trends in society, sometimes reluctantly letting go when a rule once inviolable becomes archaic, even quaint.

They do this mostly by publishing books – etiquette for couples. For men. For children. For parents. For weddings. For business. And the 896-page omnibus “Emily Post’s Etiquette,” which had its 17th edition in 2004.

Often the advice is sought after the fact, such as the woman who wrote to the institute’s Web site asking exactly how rude it was that a friend had failed to bring a bottle of wine to dinner. Or the one who demanded a ruling against a sister-in-law who dressed less than conservatively for a funeral.

“They’re basically asking us to confirm their opinion,” Tricia Post says. “We try not to give them fodder and fuel the family fight. I think people are quick to take offense when none really need be taken.”

Which brings us to America circa 2006, a place of snippy blogs, pundit shouting matches on cable TV, brawling parents of tee-ball players, roadways packed with drivers who have spring-loaded middle fingers and anger to spare.

Seven in 10 Americans think people are ruder today than they were 20 or 30 years ago, according to an Associated Press-Ipsos poll taken late last year. And more than 90 percent blame parents for failing to teach their children how to act.

In a separate poll this spring, three-quarters of people surveyed said they frequently or occasionally encounter profanity in public. And two-thirds said it’s worse now than 20 years ago.

You might think this is all good news for a business trying to show people how to behave. And it is. But the Posts are not so sure we are living in the end times of civility.

Cindy Post Senning, a former elementary school principal and great-granddaughter of Emily Post who handles the institute’s books for children, says people often confuse a trend toward less formality in society with a decline in manners.

And anyway, the old days were not always so stuffy: Post Senning says her great-grandmother used to dunk the ends of a steaming-hot corncob into her glass of ice water to cool it down for handling.

“I think it’s just the intensity and the pace of life today,” says Post Senning, who, at the same country-club lunch, instinctively flipped a knife over to face in toward her plate.

“I think it’s just – we have to make some choices. We can’t do everything we want to. Like checking your BlackBerry all the time. People say, ‘Well, I’m just checking my schedule.’ Well, nobody knows you’re checking your schedule.”

Peter Post notes that he heard from one person who was aghast at attending a wedding reception with a baked-potato bar, and another reception that featured an iPod playlist rather than a traditional DJ (or a once-traditional live band).

“If it’s meaningful to them, it’s fine,” he says. “I never want to hear the words, ‘It’s just not done that way.’ Of course, the DJs of the world are going to hate me now.”

Peter Post takes a slightly different view on the question of our incivil society. He absolutely believes people are less tolerant of others’ opinions these days, holding to their own with a possessive rigidity.

But paradoxically, he believes there are times when people trip over themselves by being too polite. Nobody says “you’re welcome” anymore, he says – the end of conversations devolving into a merry-go-round of endless thanking.

“Thank you,” he mocks. “No, thank YOU.”

In a scene straight out of “Seinfeld,” he exclaims: “She’s trumping my thank-you!”