Just pressing an on-off switch implies consenting to deeper, not fully clear rules and risks. This is hard enough to make sense of in the debate about domestic liberty. Cast in the context of two great and uneasy powers, the problem touches hot buttons that have fired some of the worst conflicts in history: territoriality, trust and arms race.

One of the first things American and Chinese officials will acknowledge when they sit down this week is how little we know about I.T. systems and national security. But it’s important they look beyond immediate issues of hacking and to the deeper problems of power in this new age. Network technology challenges many traditional international rules. The treaties of Westphalia in the mid-17th century, for instance, assumed a state monopoly on violence. But with virtual world weapons, control is harder to define.

One can easily imagine a moment in which U.S. and Chinese leaders agree to dial back tensions on some issue only to see privateering nationalist hackers on both sides take up cudgels anyway. Or consider the fact that cyberattacks usually exploit unseen vulnerabilities. So nearly every strike is a “surprise attack” — an anxiety-inducing quirk that argues against the “trust first, adjust later” approach essential for dampening the shock of the inevitable crises.

Even the most basic question of any new weapons technology — does it mostly benefit offensive or defensive military action? — is unclear in this new world. This matters, because misjudgments on this score can lead to deadly miscalculations. A hundred years ago European leaders thought the machine gun was a devastating offensive weapon. They had it wrong and World War I proved to be a five-year defensive bloodbath.

Moreover, one of the charms of new technology — the speed of innovation — means strategic arrangements made today may be obsolete tomorrow. Consider artificial intelligence: Every day, thinking machines are becoming more important for analyzing data. But as these machines develop, they become ever harder to regulate. If traditional hacking is stoppable because you can always find the hackers, machine-intelligence systems that probe and poke each other may be far harder to understand or regulate with treaties.