It’s not just rockers, rappers, and mobsters anymore. Dick Cheney does it. John Kerry does it. Samuel L. Jackson does it. Even 12-year-old Little Leaguers do it. Use the f-word, and its more pungent compound cousin, that is.

Lately, it seems Americans have become unshockable. The word that starts with “mother”—or more precisely “mutha”—delivers about as much sting as “darn.” Walk through an American city, and you’ll hear the once-unutterable obscenity bandied about on the street, across social, generational, racial, and ethnic lines. What the bleep gives? And does bad language make us bad people?

If so, it looks like we may be turning into a nation of evil-doers. According to an Associated Press-Ipsos poll conducted in March 2006, two-thirds of respondents believe that there’s more swearing now than 20 years ago. Seventy-four percent said they experience the use of profanity in public frequently or occasionally. And 64 percent said they use the F-word anywhere from several times a day (8 percent) to a few times a year (15 percent).

The question of whether coarse language degrades our social fabric has become a staple of culture-wars debates. And social critics on both the left and the right blame pop culture for all the trash talking. But popular demand, in the form of online user-generated videos and blogs, pushed the epithet marrying “mother” to the medieval term for sexual congress into this summer’s most parodied action movie, “Snakes on a Plane.”

After one blogger created a mock movie trailer in which actor Samuel L. Jackson tells his fellow passengers, “I’ve had it with these snakes on this plane!” the blogosphere was abuzz with the more obscene version of the phrase, perhaps in an homage to Jackson’s fondness for the word in his earlier film, “Pulp Fiction.” Eager to give fans what they want, the folks at New Line Cinema worked the obscenity-laced scene into the finished product.

It could be that the “Snakes” phenomenon finally has defanged the taboo around the term, and we’ve simply reached another milestone in a long history of linguistic envelope-pushing in movies and pop music. Or is it something more--a signal that Americans no longer see swearing as transgressive?

According to Dr. Timothy Jay, a psychologist and author of books on swearing, including “Cursing in America” and “Why We Curse,” trashy talking is a basic human impulse. “This language fulfills emotional needs on two levels: my need, as a speaker, to cope with some emotion, like fear or surprise, and it conveys that feeling very effectively to someone else.” In fact, says Jay, it can be a social safety valve: “It allows us to express our emotions without physicality….Once you can tell people ‘I hate you,’ you no longer have to put yourself in jeopardy to prove it.”

Despite what the AP-Ipsos survey suggests about curse-creep, Jay’s research shows that the use of obscenity and profanity has remained “very stable” over the past 20 years. In his latest field study, conducted in 2006, Jay’s research assistants listened to people talking in public around the country and computed that of 3,000 instances of swearing, the f-word remains the most commonly used curse—followed, in descending order, by, s--t, Oh my God (mainly used by women); hell; Jesus/Jesus Christ; damn; ass, suck, God damn, b---h.

“M-----f----r is down at about 17,” Jay says.Okay, so we’re a cursing culture. But have we now become totally unshockable? And is our coarse talk sinful?

“In the Christian community, such language is completely unacceptable,” says Ben Witherington, Professor of New Testament Interpretation at Asbury Theological Seminary in Wilmore, Ky. “While the obscenity you refer to is not sacrilegious in the normal sense, it is a clear violation of one of the Ten Commandments: Honor thy father and mother. I would not see this as something that gives you a one-way ticket to hell, but as the Bible says, what comes out the mouth reflects what's in the heart, and such language shows that a person is not spiritually well.”