It is far from clear that this group of leaders — the G7 also includes Germany, Britain, France, Canada and Italy — can sustain a conversation on a technology that appeared to burst on the scene so quickly, even if it was years in the making. Past efforts to get the group to take up far more straightforward cybersecurity issues usually descended into platitudes about “public-private partnerships,” and there has never been serious discussion of rules to guide the use of offensive cyberweapons. That will enable lower-level aides to discuss details of what those first regulations would look like, the officials said. But as the G7 leaders convene starting on Friday, it will be Ukraine that will dominate the conversation, at a critical moment for Mr. Zelensky, for Ukraine and for the core Western democracies now seized with an urgent mission of bringing about what Mr. Biden calls the “strategic defeat of Russia in Ukraine.”Mr. Biden often says that Russia is already defeated. But the fear permeating the seven large democracies here is that unless the counteroffensive proves highly successful, Ukraine will settle into a bloody, frozen conflict in which the best hope would be an armistice, reminiscent of the one that brought a halt to fighting on the Korean Peninsula 70 years ago this summer.

---