A Notable is a mover and shaker in the Government of a Nation. Whether as a noble, a representative of a powerful Guild or other Institution or an elected member of a republican state council they wield some amount of Influence in the decisions of that Government, and when major decisions come up will argue for whatever option best fits their goals. Generally, the available Influence in a Government trends towards 100, and Notables may compete for Influence and prestige through various actions among each other - depending on Culture and government these might range from public philosophical debates to dueling with sword or spell.
When a government needs to reach a decision, Notables vote and the option favoured by those with the most Influence wins. Notables with an Influence less than 10 must join the voting bloc of a more powerful Notable. Often one will emerge as the representative of their social class. With sufficient infiltration, the player may be able to see the deliberations in a special Political screen:
In this example the decision is how to deal with barbarian incursions in one of the Nation's POIs and possible options are graduated on a binary choice of directions - seek war or seek peace. The option currently favoured is a Counterattack, the most measured response on a War footing - a few more War voters would move the decision out to a more extreme War response. Each portrait shows a Notable and the number in the bottom left corner indicates their Influence for this decision, whether from themselves or a backing voting bloc. The number's colour indicates what they are voting for - in this case green voters favour war and red voters favour peace, with white favouring moderation and pulling back against either extreme.
Modifiers to a Notable are indicated on the bottom right of their portrait. In the case of the bottom right duke, the coin indicates he speaks for the major bloc of the noble class. The two Notables next to the Queen have been granted formal titles in the administration - the Keeper indicated by a book is counseling peace, while the Marshal indicated by a banner is counseling war. He also gets additional Influence (subtracted from the Queen) for this particular decision as it is a military matter in his purview. In the example two Notables also have a red border - this indicates that they are particularly invested in this decision - the Marshal because of his military purview and another Duke because the POI under threat is in his nominal control. If they do not carry the day and the decision goes in the other direction (i.e. peace, in this case) these Notables may suffer a loss of Will and their relationship with those who voted against them may suffer.
Old Ones have many options to manipulate the voting of Notables, including blackmail, bribery, favours and corruption.