One of my favorite quotes:

"Politics has nothing to do with what a person personally advocates for." - Norman Finkelstein

An example he often gives is advocating for a world without borders. You can advocate for it, and create a group of like minded peiple and write blogs about it, but it will be like creating a cult. Politics, according to him, starts with what the people want. It has to have some concrete proposals and practical momentum that are accepted (or at least not resisted) by the general public.