Enough diagnosis. If someone with actual power read this series and asked what to pull, there are four levers, and they’re not all equally hopeless. Two of them are better than most people think and one of them is available to a single country acting alone, which is the closest thing to good news I have.

The first is compute. Training a frontier system takes an enormous quantity of specialized hardware and a great deal of electricity, and both of those are physical, countable, and hard to hide. The chips are made in a handful of facilities using equipment produced by an even smaller number of suppliers. Very large power draws show up on grids. This matters because the thing that kills most arms control is verification: you cannot enforce what you cannot see, which is why agreements about intentions fail and agreements about detectable objects sometimes work. Of everything in this post, compute is the only lever attached to something you can count. That’s a genuinely lucky accident of how this technology happens to work, and it will not last forever, because efficiency improves and every year the same capability needs less hardware. The window is real and it’s closing on its own.

The second is treaties, which everyone dismisses and which have actually worked before under specific conditions. Look at what the successful ones had in common: a small number of parties who mattered, a physically detectable activity, inspection with teeth, and a shared belief that the alternative was mutual disaster. This situation has the first two and a version of the fourth. What it lacks is inspection, and inspection is the whole thing, so a treaty here would have to be about facilities and hardware rather than promises about behavior. That’s a much narrower agreement than the grand pauses people imagine, and narrow agreements are the only kind that have ever held.

The third is liability, and it’s the cheapest and most underrated lever in this entire series. If the people who build and deploy these systems carry legal responsibility for what the systems do, the whole calculation changes on its own, with no international coordination, no new agency, and no ability to predict the future. Insurers start asking questions. Caution becomes a line item rather than a virtue, and line items survive competitive pressure in a way that virtues never do. One country can do this alone. It requires no agreement with anybody, and companies operating internationally cannot easily route around the jurisdiction where their customers are. If I could have one thing, it would be this one, and the fact that it’s the least discussed tells you something about who’s shaping the discussion.

The fourth is unplugging, which an earlier post covered and which I’ll leave at one line: the switch exists, the price rises every quarter, and it’s the lever you reach for after the other three failed.

Now the structural problem that sits on top of all four, and it’s the reason this post is in Act 2 rather than Act 1. Coordination gets harder exactly as it gets more important. When systems are unremarkable, restraint is cheap and nobody bothers. As they approach something decisive, the payoff for being the one who doesn’t restrain rises, and so does everyone’s suspicion that the others are defecting. The moment when a pause would matter most is the moment when the cost of pausing, and the perceived cost of being the only one who did, are both at their maximum. That’s not cynicism about human nature, it’s arithmetic about incentives, and this series made the same point about the labs in its first fortnight. Restraint is easy when it’s pointless and nearly impossible when it isn’t.

I’ll argue against my own pessimism, though, because the historical record is not as bad as doomers pretend. Countries with every incentive to defect have sometimes held to inspection regimes for decades. Whole categories of weapon have been given up. Technologies that could have spread to everyone spread to fewer than the forecasts said. None of that was inevitable and all of it required people who did the unglamorous work of building verification systems before there was a crisis. The pessimistic case here is a prediction about incentives, not a law of physics, and predictions about incentives have been wrong in the good direction before.

What’s missing isn’t ideas. All four levers have been described in detail by serious people. What’s missing is anyone whose job it is to pull one, which was Act 1’s argument, and a public that treats this as a live political question rather than a science fiction discussion, which is Act 3’s.

Tonight’s exercise. Pick the lever you’d choose and work out who would have to move first. Name the actual role: a legislator, a regulator, a court, a trade ministry. Then ask what would make that person’s next year better for having done it, because that, not the merits, is what determines whether anything happens. If you can’t find the incentive, you’ve found the real problem, and it isn’t technical.