Once, Superpower Summits Were About Nukes. Now, It’s Cyberweapons.

But with the ease of denying responsibility and the wide range of possible attackers, the traditional deterrents of the nuclear age no longer work.

GENEVA — For 70 years, meetings between American presidents and Soviet or Russian leaders were dominated by one looming threat: the vast nuclear arsenals that the two nations started amassing in the 1940s, as instruments of intimidation and, if deterrence failed, mutual annihilation. Now, as President Biden prepares to meet with President Vladimir V. Putin here in Geneva on Wednesday, for the first time cyberweapons are being elevated to the top of the agenda. The shift has been brewing for a decade, as Russia and the United States, the two most skilled adversaries in the cyberarena, have each turned to a growing arsenal of techniques in what has become a daily, low-level conflict. But at summit meetings, that sort of jousting was usually treated as a sideshow to the main superpower competition.