By interacting with others in a thoughtful and purposeful way, we can accomplish what would otherwise be just be whimsical thinking about how things ought to be. This is not about politics per se but about coming up with good ideas and practical solutions to the misery of human incontinence and mental affliction. Contrary to popular belief, good ideas do have a positive impact upon society, either directly or through public policy. The impact of your ideas largely depends upon breath and depth of perspective. You also have to write well.
Good writing knows no bounds.
You cannot change the world only by talking within your small circle of friends. You have to reach beyond. A well written letter, from the recipient's perspective, can be very persuasive. After all, there still are not so many people who really write well. And most policy makers do not have much time to think for themselves.