As more and more human activities--involving governments, businesses, individuals, and society as a whole--move into "cyberspace," they become exposed to a new set of vulnerabilities that can be exploited by a wide spectrum of "bad actors" for a variety of motives. This paper discusses questions such as: (1) How serious are the likely threats to different segments of society, both today and in the future, from cyberspace-based attacks by various "bad actors"--such as hackers, criminals, disgruntled employees, terrorists and nation-sponsored informational attacks? (2) What are the current best strategies for achieving security in cyberspace? (3) What roles and missions should various national entities (police, defense forces, local governments, etc.) be assigned to counter these threats, given that it is often unclear who the perpetrator is, and from where the threat emanates? (4) Are there specific services and institutions in each nation--which we term a "national interest element"--that play such vital roles in society that their protection from cyberspace-based attacks should be of national concern? This paper does not answer all these questions, but at least attempts to structure the discussion so that meaningful answers can be obtained.