Maine may adopt a law prohibiting smoking in cars containing children, based on a year-old city ordinance in Bangor that’s never been enforced.

That’s right. Not once.

“My sense is that we’re getting a lot of voluntary compliance,” said Bangor Police Chief Peter Arno, in a Jan. 19 article in the Bangor Daily News. Arno also noted the city of Bangor has never issued a citation for violating Maine’s restaurant smoking ban, either, and that was passed eight years ago.

A quick scan of Sun Journal archives found two convictions, both in September 2007 oddly enough, for smoking in a prohibited place. In Maine, this means a bar, pool hall, government building, restaurant, public bathroom, private residences used as child-care facilities, theaters and other public places, jury roomsthe list is extensive.

Ubiquitous prohibitions have been critical tools in curbing smoking, which has earned Maine accolades.

Just this month, the American Lung Association again gave Maine the high national marks in its annual Tobacco Report Card. Maine’s grade did slip in cigarette taxes – the association would prefer them higher, of course – but this would be progress through problematic policy.

In pure terms of stopping smoking, Maine is tops. Through strong prohibitions, and equally virile public information campaigns, this state is a national leader in reducing tobacco use, especially among children and teens.

Like any good thing, though, it’s possible to have too much.

This is our concern with the prohibition on smoking in vehicles containing children under 18, which given Bangor’s experience, seems a great public health campaign wrapped in an unenforceable statute.

Only a “knucklehead,” to use the word of Rep. Bob Walker, a Republican lawmaker and physician, would smoke with their young children in the car. Smoking alone is just as ill-advised, but it is, at least, self-victimization. Subjecting children to the dangers of second-hand smoke is just stupid.

As a culture, we understand this, and are changing our behavior. Last May, the Centers for Disease Control and Prevention released a study finding that 75 percent of U.S. households were smoke-free. Seventy percent of Maine homes were smoke-free, the study said, an increase of 75 percent from the early 1990s.

Good laws have contributed to this, alongside strong public health campaigns through the tireless advocacy of groups like the lung association and others. Although these sides are working for the same gains, however, they must remain mutually exclusive.

Though the vehicle smoking ban is well-intended, it looks to be rarely, if ever, enforced. It is also an uncomfortable infringement on civil liberties.

As a public health campaign, however, one endorsed by the state and executed by the same agencies that have been so successful so far, the idea is a winner.