>most studies have shown that enforcement does reduce the number of drunk driving deaths

But there are still 10k of them a year. Why, by your logic, don't we tighten up enforcement until there are none of them? What justifies stopping anywhere short of that?

> Under your system, a boycott is the only way to stop them?

How did they manage to build a plant with a 10% per year chance of catastrophic failure? It takes thousands of people to build a nuclear plant. Why would all of them participate in such a thing?

> Under your system, what do we do about it?

Under our current system, what do we do about it? You have described the current world situation: someone could have such a lab right now and we couldn't stop them. So why hasn't it happened?

> I really don't think you've thought this through.

I'm not sure you have either. You are assuming a world in which we have eliminated all penalties against people who have not done actual harm, but nothing else has changed from our current world. That is not at all what I have been assuming. I am trying to contrast what we have now--a system in which the law penalizes people who have done no actual harm, and which has evolved for a long time under that assumption--with what we would have if a system in which the law does not penalize people who have done no actual harm had evolved for a long time under that assumption. In such a world, many, many things would be different from today's world.

As an illustration, I'll redescribe your two scenarios:

A company wants to build a nuclear plant on Lake Michigan. However, when they try to acquire the land, they find the landowners asking what they are going to use the land for, and when they say a nuclear plant, they start getting asked all kinds of hard questions about the risks involved. They can't give satisfactory answers, so the landowners refuse to sell. Similarly, when they try to recruit people to help work on the plant, they find the prospective employees asking the same hard questions, and refusing to work for them when they don't get satisfactory answers.

A lab wants to manufacture biological weapons. However, they are unable to get funding to even start, because there are no dictators or similar insane rulers to sell to. Plus, once the lab's employees find out what the owners are thinking, they all quit.

In short, in our current world, where we allow the law to penalize people preemptively, everyone expects the few people who make the laws to be responsible for stopping people from doing harmful things. So nobody feels individually responsible for doing it. In the world I'm describing, where everyone understands that the law won't step in until actual harm is done, everyone feels individually responsible for stopping people from doing harmful things, which means stepping in preemptively based on their own individual judgment instead of expecting the law to do it.

Would such a world be free of harmful things? Of course not. But neither is our current world. The question is, would the world I'm describing have fewer harmful things happen? Would it have fewer than 10k drunk driving deaths a year? We don't know because we can't run a controlled experiment, but I think it's quite possible that the answer could be yes.