I remember when I had my first taste of politics in D&D. Before that all the adventures I had run and I the adventures I had participated in had a clear plan from the outset. Before we even sat down to play, the GM had an "adventure" in mind. But when one of my friends ran a highly political Birthright campaign, the structure was different. He didn't come to the game with any kind of adventure structure thought out in advance. He just came with a situation and NPCs. I thought it was fantastic.
At first it took me a while to realize what he was doing. Once I sensed he was running things differently, I talked to him about his preparations and he told me he just made a bunch of NPCs and power groups before hand, but the real important developments happened in game when he tried to decide how the NPCs reacted to what we were doing. Now this last bit I kind of understood, from the Living Adventure concept in Ravenloft, but even then it was done within a structured adventure scenario. This was much more free form. My friend hardly referred to notes or maps at all, and when he did so it was with a simple glance. I envied that he was so able to participate fully with the players without being chained to a dungeon map or adventure outline.
Keep in mind this was before the internet was huge like it is today. We had an internet back then but most of us were not on it and it simply didn't have the volume of users it has today. So something as simple as finding a new way to run a campaign was not an everyday experience. You couldn't simply google "adventure+design" or "political +campaign+RPG". It primarily came from existing RPG books or seeing things done first hand in a campaign. So while this might seem like a minor thing to marvel at, and others had clearly been doing this sort of thing for some time (both in print and at their table), it was entirely new to me.
I don't recall the specifics of the campaign but I do remember we had freedom to move, to invent and plan, to forge ahead how we wished. However we were up against people who felt just as clever as us, so there was a real sense of inhabiting a social landscape where actions had consequences and fallout. This was also a highly political game. Because of that, I learned to associate politics and intrigue with freeform adventure and player freedom.
After that I would try to incorporate my friend's style into my own campaigns. It didn't come naturally to me but over time I became quite comfortable with it. It had some significant advantages. One was less prep. There may have been some initial prep in advance but I found these campaigns, once they got some steam of their own, propelled themselves forward with minimal upkeep from the GM. The other was I felt much more plugged into the experience as a GM.
I mention this because in my current Sertorius campaign things have grown increasingly political. The campaign just started so we began with a somewhat simple adventure structure to give it an initial thrust, but now things are developing and those initial training wheels can come off. Alliances are forming and it looks like we may have a good deal of intrigue in the coming months.
From a GM point of view this is exciting because you don't know what the players are going to do. Things could go in any number of directions. Players can make surprising choices, befriending enemies, betraying friends and finding a way to cobble together an influential power block.
Campaigns like this force you to think things through. What happens if the King's brother dies under a cloud of suspicion? What happens if those rumors the players started in the capital spread to the countryside? What happens if the players ally with a nearby Hill Tribe to take an important town on the borderlands? What would the council do when they realize the players are slowly weakening their grip on the kingdom?
It is not merely a game of "what if" it is also a game of "what now". You have to think throughout he ramifications of events from each session and incorporate them into the next. In political campaigns things often shift and change but also stay somewhat the same. And if the players win the political game, if they obtain what their after, that just leads to more adventure. Once you have power, you have to defend it.