How’s this for a puff of nannyism: Movies can now receive an “R” rating for depicting a perfectly legal act.

Thanks to pressure from anti-smoking groups, lighting up onscreen will now factor into the ratings bestowed by the Motion Picture Association of America. The MPAA announced the move last week.

And filmgoers who like a touch of realism in their flicks got off lucky: The MPAA bragged it had resisted calls to stick a mandatory “R” tag on any movie where cigs are smoked. Way to stand up for artistic freedom!

I may be a native North Carolinian, but I’m not a smoker – never have been – and have no love for cigarettes, cigars, pipes, chaws or snuff. In fact, I recall the sheer number of cancer-stick addicts as the worst thing about living in Europe.

I wish the cussed things (cigarettes, not Europeans) had never been invented. They aren’t called “coffin nails” for nothing.

Still, I’m not certain whom the MPAA and anti-smoking groups think they’re protecting.

Tobacco-control groups regularly point to studies postulating a link between onscreen cigarette use and youth smoking. Hence the ratings change.

But a bit of perspective amid the crusading would be nice.

Other studies, including one from the University of North Carolina, show that children’s exposure to all sorts of media – including unsupervised access to television – also has a correlation with smoking.

I wonder how many well-intentioned anti-smoking advocates let their own children have bedroom TVs. Or how long it will be before interest groups try to regulate TV owners’ ages.

These days, any kid with a pulse knows about the dangers of smoking, can cite chapter and verse why it’s a stupid habit.

And any impressionable child headed to the movies will first have to run the smokers’ gauntlet outside the mall before he even steps foot into the cineplex.

What’s next: A restraining order banning kids from coming within 500 feet of the entrances to government buildings, restaurants, offices, private homes or anywhere else smokers – glamorous or otherwise – might be spotted?

If you think the down-with-tobacco crusade stops with movies, think again. British anti-smoking groups have moved to ban the practice in private vehicles, alleging that lighting cigarettes causes accidents. What they mean is inattention in all forms – including changing CDs, eating while driving and swatting at children – causes accidents. Will they try to ban child passengers, too?

Like it or not, cigarettes are legal. And in many cases, puffing onscreen is realistic.

I can’t imagine the character of Edward R. Murrow in “Good Night and Good Luck” without his ever-present cig. Or the fate of the satirical “Thank You for Smoking” under the MPAA’s new guidelines.

Or the leg-crossing interrogation scene in “Basic Instinct” where Sharon Stone uttered the movie’s best line: “What’re you going to do? Charge me with smoking?”

Yep. You and your movie, too.

It’s only a matter of time before other do-gooders leap on the you-can’t-show-that bandwagon.

In 2004, obesity replaced smoking as the nation’s leading cause of preventable death. And car accidents kill 45,000 Americans each year. So while smoking can garner a stricter rating – meaning a flick will likely have a smaller audience – daredevil driving or scarfing cheeseburgers and Coke is still OK. For now.

I don’t look to the movies for examples. I look to them for escapism. And I’d be willing to bet many kids do, too. After all, the fun of movies is watching others do what you can’t or shouldn’t.

You cannot legislate away the real world. At what point do grown-ups allow kids to see scenes that serve as catalysts for parental discussions on right and wrong?

And therein lies the problem: It’s parents’ responsibility – not that of movie directors or trade associations – to teach kids the consequences of harmful behavior they witness. Anyone advocating otherwise is just blowing smoke.