Hey @robmolecule, this can be an interesting and good topic to discuss. All tough I think that the "fair use" policy is a wide topic. I would ask myself if it would be still considered "Fair Use" if I would earn money on using copyrighted work.

There are four factors that you need to keep in mind when you would write about political figures.

1. What is the purpose of the use (commercial nature or nonprofit/educational purposes) of the copyrighted work?
2. What is the nature of the copyrighted work?
3. What is the amount/substantial portion (copy for example) related to the copyrighted work as a whole?
4. What is the effect by using the the copyrighted work upon the potential market?

Since most content published on Steemit is for commercial use, you cannot publish copyrighted work that is not licensed under the four different Creative Commons licenses mentioned in the blog post above. While I am not sure if declining pay-out is seen as the right way to point out that the post is not published for commercial intend, I find it riskily to use copyrighted work on the Steemit Platform.

Hopefully this would cover your question regarding the copyright fair use policy and Steemit.