The problem with reductio

I'd thought mandatory ski helmets and "social costs of skiing" an appropriate reductio to including the private costs of a drinker's drinking as socially relevant. Then The Herald started pushing for mandatory ski helmets.

I'd also suggested a sex tax as another reductio: if STDs put costs on the public health system, doesn't the state have a compelling interest in what you get up to and with whom?

And here, from the loonier parts of the US:

Politicians are always talking about taxes. Some of them want to “soak” the rich; others want to raise “sin” taxes on alcohol and cigarettes. But I can think of one “consumer item” we’ll never see a tax on: sex. But maybe we should. Sex—the wrong kind of sex, that is—is driving up the cost of government.

In a recent column, marriage expert Mike McManus explores the high cost of out-of-wedlock sex. For instance, over 7 million American couples live together. Four out of five of those couples will break up without ever tying the knot. But, McManus writes, if they’ve had a baby, many of those mothers and children will be eligible for Medicaid, housing and day-care subsidies, and food stamps.

Second, even when co-habiting couples DO marry, according to a Penn State study, they suffer a higher divorce rate than couples who don’t live together first. On average, each divorce involves one child. And like the never-married mother, the divorced mom is often eligible for many government benefits. According to the Heritage Foundation, McManus writes, “13 million single parents with children cost taxpayers $20,000 each, or $260 billion in the year 2004.” The total probably comes to $300 billion today, McManus says.

And that’s just the beginning.

A child born out of wedlock is seven times more likely to drop out of school, become a teen parent, and end up in prison. They are 33 times more likely to be seriously abused.

And we’ve all heard of the high rates of STDs affecting America’s teenagers—diseases that cost billions of dollars to treat.

So maybe we SHOULD consider a tax on non-marital sex—everything from one-night stands to living together arrangements. It’s costing us a lot of money. And such a tax might indeed pay off the national debt.

He goes on to propose, rather than taxes on sex per se (which he seems to oppose less because they're invasive than because they're impracticable and unpopular), a bunch of pro-marriage initiatives.

If we let fiscal externalities determine the appropriate range of government regulatory activity, there isn't much that's out of scope.