MY COLLEAGUE noted the other day the discussion Matthew Yglesias has been having with his readers over whether liberals and libertarians can agree on some regulations they both hate. So, here's a regulation I hate: you're not allowed to swim across the lake anymore in Massachusetts state parks. You have to stay inside the dinky little waist-deep swimming areas, with their bobbing lines of white buoys. There you are, under a deep blue New England summer sky, the lake laid out like a mirror in front of you and the rocks on the far shore gleaming under a bristling comb of red pine; you plunge in, strike out across the water, and tweet! A parks official blows his whistle and shouts after you. "Sir! Sir! Get back inside the swimming area!" What is this, summer camp? Henry David Thoreau never had to put up with this. It offends the dignity of man and nature. You want to shout, with Andy Samberg: "I'm an adult!"

I would gladly join any movement that promised to do away with this sort of nonsense. For example, Philip K. Howard's organisation "Common Good" (TED talk here) works on precisely this agenda. Common Good's very bugaboo is useless, wasteful legal interference in schools, health care, recreation, and so on. But what you quickly note with many of these issues is that they're driven by legal liability concerns. You have a snowblader in Colorado suing a resort because she crashed into someone. You have states declining to put up road-hazard signs because the signs prove they knew the hazard was there, which could render them liable for damages. You have the war on children's playgrounds. The Massachusetts swimming ban, too, is driven by liability concerns. The park officials in Massachusetts aren't really trying to minimise the risk that you might drown. They're trying to minimise the risk that you might sue. The problem here, as Mr Howard says, isn't simply over-regulation as such. It's a culture of litigiousness and a refusal to accept personal responsibility. When some of the public behave like children, we all get a nanny state.

But this is why I think the question of liberal sympathy for a project of scrapping regulations needs to be a little more specific. Occasionally, you hear libertarians argue that regulatory agencies such as the Food and Drug Administration should be cut back or eliminated, since the fear of legal liability will by itself compel companies to ensure that their products are safe and effective. I think this idea is approximately 180 degrees wrong. Trying to establish social norms via lawsuits is part of what's cramping liberty in everyday American life. It's precisely the reason why I can't swim across that pond in Massachusetts.

I don't always think that a comparison to European social democracies is valuable in establishing the alternative pole of a "regulatory state" in such conversations. But for comparison's sake, here's a picture I took in Amsterdam, not generally thought of as an under-regulated city, a couple of weeks before I took that picture in Massachusetts.

That's my daughter swimming in the River Amstel. Inside city limits. How clean is the water? Well, I don't really know, which is why, for the first few days we were staying on our friend's houseboat, I didn't let her swim. Even though all the people on the other houseboats, and their kids, were doing it. Then a close friend came over with her eight-year-old son, who insisted on swimming, and it just became impractical to stop them. So what the heck. In fact, I'd tried to look up the official position on this question, and found that the government advises against swimming in rivers anywhere in the Netherlands, because of boat traffic and water current issues. But the thing is, as long as you don't do something gratuitously stupid or make a flagrant nuisance of yourself, nobody's going to stop you.

If I'd tried letting my daughter do this in, say, the Potomac River in Washington, DC, I would have likely been arrested. The reason you can do it in the Netherlands is that if anybody tried to sue the city of Amsterdam because they or their child had been injured while swimming in the river, the suit would almost certainly be dismissed. (One woman is in fact suing the city because her 19-year-old son drowned at an unofficial beach in 2004, but the issue is that it was a popular beach with hundreds of bathers and fast-food shacks that the city had allowed to operate for years without any official lifeguards or warning signs. Nevertheless, her suit was rejected by the Dutch courts; she's now appealing to the European Court in Strasbourg. This is the exception that proves the rule: it's much harder to win such a suit in the Netherlands than in the United States.) Essentially, you still have the freedom to swim in the river in Amsterdam because people assume you have the common sense to avoid stupid behaviour, like diving in when you don't know what's underneath, or not keeping to the sides of the river during barge traffic hours. And if you don't, it's nobody's fault but your own.

But there's another reason why I can let my daughter swim in the Amstel, and that is that I'm pretty sure that in a well-regulated country like the Netherlands, the water is reasonably free of heavy pollutants and raw sewage. (I would not, for example, let her swim in the Mekong.) This, I think, outlines a useful distinction between different kinds of regulation. I am perfectly capable of assessing for myself the risks of swimming across a small pond in Massachusetts, or the risks of swimming in the Amstel when lots of boat traffic is around. I don't need regulations to protect me; I have common sense. What I can't assess for myself is the risk that the water is contaminated by raw sewage. For that, I need a regulatory agency that stops households and businesses from polluting the river. To generalise: for risks I can assess myself, I don't want regulations that prevent me from doing as I please just because I might end up suing the government. For risks I can't assess myself, I do want regulations that give me the confidence to do as I please. One kind of regulation stops me from swimming in a pond in Massachusetts. The other kind lets me swim in a river in the Netherlands. One kind of regulation makes me less free. The other kind makes me freer.

I'm not saying the Netherlands has struck the right balance, overall, between freedom and regulation. On the commercial side, the Dutch feel themselves to be heavily over-regulated. But I do think the comparison helps to identify how regulation and freedom interact. And to pull back one more level, I think another thing that makes people feel freer to do things like swim in a river is the confidence that if anything goes wrong, they have health insurance. At that point you start to get into a broader discussion about the differences between what liberals and libertarians mean when they talk about being free.