Perhaps a quarter of the men look like they have just come from grilling brats at a tailgate party. About a fourth of the women, and even girls as young as 12 or 13, look like they are at the beach, or at a pajama party, or offering services on a Tijuana street corner.

But they are at the airport — just about any American airport — and collectively they are just one more sign of the coarsening, or maybe it’s the cheapening, of modern culture.

Another example: At a family tourist spot just the other week, one couldn’t help overhearing the loud conversation of several 13- or 14-year-old girls. “I don’t care who he’s married to: I’d have an affair with Bill Clinton any day.”

“Oh, yuck. Not him. But I’d have one with Obama.”

“Yeah, I’m with her: Obama but not Clinton. And, like, definitely, not with, like John Edwards. He thinks he’s cute, but he’s just too, like, you know.”

The first one: “Yeah, not Edwards. But I still think Clinton would be fun.”

BACK AT THE AIRPORT: There’s a guy with shorts that barely cover his hips, and his big gut is hanging over his non-belted belt-loops, and his T-shirt looks very much the worse for wear. And over there is a 55-year-old woman with ratty shorts not much bigger than a bikini, and a tank top, and a long gray-blond ponytail, and a massive spider tattooed all across her upper back. Oh, and wait, can you believe that 15-year-old in the spandex and glitter? Or what about the 11-year-old boy with his tight preppy shirt and his baggy pants hanging off his hips, with two inches of boxer shorts showing above them?

Or you’re at the movie theatre, and the perfectly decent-looking couple is commenting out loud at all the action 15 minutes after the movie has started. Or you’re on the highway, already going 73 in a 70 zone and with cars both in front and to the side of you, but the guy behind you is riding just two inches off your tailgate. And it’s nighttime, and his bright lights are on — blindingly so.

Or you are at the mall, trying to find the movie theatre, and the concourses are teeming with people of all ages and races and cultures, all throwing money around like its confetti, and absurdly young girls and boys are in T-shirts that say things like “I’m too hot for you to handle,” and “I’m a bi**h and proud, so get used to it” (except that the “b” word is actually spelled out). Yet if you poll the adults in their families — adults in households with four cell phones and two cars and three TVs and three computers and vacation plans for Disneyworld next week — they will tell you that times are really tough and they just think it’s so much harder to make ends meet than it was a generation or two ago.

But they admire the Sopranos, because they know how to look after their family and not let the American rat race get them down.

AND IT GOES WITHOUT SAYING that prime-time TV is a sewer of illicit sex and foul language and other filth. Internet porn, Xtreme video games, so-called “music”…even “kiddie” arcades are full of so many disturbing images and pursuits that it’s hard to know if there is anywhere that is “safe” for good, healthy, family fun.

One need not be a “prude” to think there’s something seriously amiss in a culture like this, a culture that knows not the difference between a hero and a celebrity, between bravery and bravado, between virtue and wealth. One need not know how late in the year a man should wear white, in order to know how to be courteous or at least how to avoid being just plain rude. Or why it’s important to avoid being rude in the first place.

Meanwhile, we in the news business give you 24-hour TV coverage of Paris Hilton’s jail term and Lindsey Lohan’s latest binge. And then we complain that the blogs are dangerous because they don’t provide a proper “gatekeeping” function to screen out real news from garbage. Yeah, right.

The cultural rot isn’t just a U.S. phenomenon, either. Go just about anywhere in the world, and the story is the same or worse. Just about anywhere that reasonable wealth meets modernity, the lowest common denominators leave higher aspirations in the dust.

In her infamous and infantile commencement address from Wellesley College, Hillary Clinton urged Americans to practice “more ecstatic and penetrating modes of living.” But we could all probably use a little less ecstasy and a lot more decency instead.

SO, WHERE IS ALL THIS GOING? What’s my point? Or, more appropriately, what’s the solution?

I dunno.

If I could assign everybody in the country a viewing of Sergeant York, and of Hotel Rwanda, and of The Lives of Others,” I would. Then I’d give everybody a reading list of books, fact and fiction, in which flawed but heroic figures stood up for truth and beauty and “the right thing” for the sake of the truth and beauty and right things themselves. Then maybe I’d make everybody read the Beatitudes again, and probably the Ten Commandments.

And finally I’d have every person on Earth read George Washington’s “Rules of Civility & Decent Behavior in Company and Conversation,” all 110 of them closing with the last and best: “Labor to keep alive in your breast that little spark of celestial fire called conscience.”

None of that is likely to do any good for the slob with the beer gut hanging over his short shorts. But maybe the rest of us can find a way to promote a consciousness of conscience. Or at least teach our 12-year-olds that bi***hood isn’t a status symbol, but a condition devoutly to be avoided.

And so, for that matter, are Bill Clinton and Barack Obama to be devoutly avoided, but that might be a different subject altogether…