On Matters of State · 3:25am Mar 18th, 2017
In Equestria, the branches of government that handle matters related to one another are referred to as 'Guilds'. For example, all matters relating to magic (not just unicorn magic) are handled through the Mage's Guild (full name: Her Majesty's Mage's Guild of Equestria). Matters pertaining to education are handled by the Scholar's Guild, matters pertaining to the law are through the Inquisitor's Guild, matters relating to the military are through the Tactician's Guild, etc, etc. The guilds themselves have their own branches within them, but more or less have the same structure, and their own designated head.
Presiding over all the guilds are Princess Celestia, and Princess Luna---the so-called “Elder Royalty”. Others like Twilight Sparkle, Blueblood, Gleaming, and Cadance have political clout, but as their responsibilities and influence lie primarily outside of Canterlot, they are seen by many as lesser authorities, almost like the heads of their own, unique guilds.
The actual political power Twilight and the others have isn’t clearly defined as of this time, and likely won’t be in Fecundity's universe. All that really matters is that when it comes to matters outside of their own spheres of influence*, they don’t have the same level of pull. BUT, it should be noted that they’re all still members of the Equestrian Royal Family, and thus have direct, familial ties to Celestia and Luna.
The only exception to this is in matters of emergency, such as when Celestia and Luna were kidnapped by the plundervines. In these times, the “New Royalty” is next in the chain of command, starting with Twilight Sparkle (probably should’ve been Blueblood if going by seniority, but I’d bet good money the writers of that episode forgot Blueblood existed).
*An example of 'spheres of influence' would be as such. Twilight Sparkle is the "Princess of Friendship", but she also has considerable authority in matters of magic, national security, anything pertaining to Ponyville, and/or the Elements of Harmony. She's not the princess of these things, but her accomplishments and experience garner her considerable sway.
I like this. Attempting to logic out governance and politics as they work in Equestria is enjoyable, as is reading other people's interpretations. This is almost as good as when you write macro.