A useful skill for trying to sway large swaths of the population to support a noble's position, and point the torches and pitchforks at the other fellow. This skill implies a character has the knowledge of how effective efforts to sway a population might be, it doesn't necessarily suggest they have the means to do so. The noble chained up and gagged in a cell awaiting execution isn't going to be swaying anyone.
0: I HAVE A VOICE AND I DESERVE TO BE HEARD, I WILL YELL AT PEOPLE UNTIL THEY AGREE. This never works.
1: Handing out flyers and making signs. In theory, this actually helps. Despite any evidence supporting it.
2: There is no sufficient skill in hassling people to get the word out and make people exasperated.
3: People have heard of the cause you are supporting. Probably too much.
4: Pretentious people have been swayed by your arguments and act like they were supporting it from the start.
5: You can pretty much start a mass societal movement with little effort.
6: Neat! You started a religion by accident. Apparently you're a deity now.