Joseph S. Nye, the University Distinguished Service Professor at Harvard, has a major paper in the MIT Press Journal, Winter 2016-2017, “Deterrence and Dissuasion in Cyberspace”, with access link to the 71-page PDF here (free).
Nye discusses for major strategies: (1) Punishment or retaliation (2) denial or defense (3) entanglement (4) taboos or norms. Some of his scenarios refer to LOAC, or the Laws of Armed Conflict.
Nye mentions the possibility of threats to power girds, and doubts that they can be fully prevented by “air gaps” between grid or infrastructure pieces and the public Internet
He mentions the importance of rogue states or non-state actors. One of his concepts, of norms, would preclude attacks on targets that have civilian use only (this might include political parties). Yet that seems to be the point of attacks by entities like North Korea, or some hackers motivated by ransomware (often in Russia or former Soviet components), or radical Islamists who resent modernism. North Korea attacked a corporate entity outside its borders, Sony Pictures, in the US, for mocking its leader. It seems as though a sufficiently radical and nihilistic actor could be motivated by asymmetric targeting of individual speakers in the US or other western countries just to prove it could wreak havoc with all parties associated with a particularly provocative person or private business.