Question

Two of the most powerful tones in writing are
Answer

honesty and commitment.

humor and sarcasm.

sincerity and respect.

wit and jealousy.

Answer 1

I would say humor/sarcasm. Both are potent weapons when seeking social change. Humor almost begs repeating, thus broadening your audience (assuming it's actually funny). Sarcasm has the benefit of allowing the author to hide behind his work, protesting it was written in all seriousness, while still tweaking the targets nose.