Why not both? Filter support would mean you'd have to update your list continuously based on current politicians and depend on certain words being used in the title/body.
A tag would still mean you'd have to depend on OP to select the right one (or perhaps on a mod to assign the right one), but at least the amount of variables would be infinitely less complex
In video form https://www.youtube.com/watch?v=ZhEoIebL6L0
edit: invidious link: https://inv.nadeko.net/watch?v=ZhEoIebL6L0