Table of Contents for Governance Systems Design
theory of the unitary executive (in foreign/military affairs)
states of emergency
CEO? paris commune and communists both tried to do without a chief executive officer (executive committees) -- in the case of the communists the effect was merely that someone took power anyway, but without procedural checks such as term limits
CEO determines direction vs cabinet collectively determines [1]
in the latter system: https://en.wikipedia.org/wiki/Cabinet_collective_responsibility (similar to democratic centralism, but just in the cabinet)
Many books have been written on this so we won't get into it much here.