What's your intended purpose for the legal document? Because legal document or not, depending on the content of the work backlash may reach you regardless of the document. Unless you would like the client to keep you anonymous as the artist.

I would suggest not taking this commission. Even if you're doing it for someone else, people won't care and still associate you with the art, and think / claim / defame you as someone who endorses the thoughts in the image.

Maybe look into existing indemnification clauses? Usually the publisher, but someone might come after you for profiting off their intellectual property.

You should probably talk to a lawyer experienced in these areas. :-)

These may be utterly irrelevant depending on the proposed subject and usage, but many furry sites have takedown clauses which do not consider fair use and parody as an exception; and other sites may have policies against disparagement of other members.

Anytime I have to think to myself, "should I ask a lawyer before I do this thing?" the thing is probably not a good idea. If you feel the need to create a legal document to cover your butt in case of backlash, it might be a better plan to just turn down the commission.

Basically, the simplest thing would be to make a contract, with a description of the work (in as much detail as possible, including where they intend to use it), your TOS, the indemnity clause, and payment plan. Have them sign it and send it back to you, digitally or on paper (or both!) before you start work, and keep emails/notes/logs where you've discussed this as well (and anything about changes, if they make any).

A very broad example indemnity clause could be:

You (the commissioner) agree to indemnify me (the artist) against any liability, claims or penalties arising from publication or other use of this artwork, including but not limited to copyright, defamation, and/or other losses or damages (direct, indirect, or consequential), with interest.
You also agree to pay all legal, professional and associated expenses relating to any such claim.

Switch the you/the commissioner/artwork to the same as you have in your TOS so that it fits in better.

If there's anything else you're concerned about, list it in there, but make sure to keep the part after 'and/or'. If you're too specific, you can accidentally limit the clause, and end up liable when you didn't mean to be.

(disclaimer: I am not a practising copyright or contract lawyer, so if you act on this advice it is at your own risk. if you want more examples, try searching (("indemnity clause" + example + [your country])) or (("indemnity clause" + example + artist)).)

Glad to be of help! That's why I said to switch the terms out to what you're comfortable with - in my area, the person requesting work is a commissioner, and the artist is a commissionee (like how an employer is the one giving a job and the employee is the one doing it). As long as it's clear between you and in your contract who does what, it's all good.

BE CAREFUL. There's a possibility of you taking the heat in the lawsuit even if there's an indemnity clause. 1) A well paid lawyer can nitpick a contract and nullify it by finding a part that's unenforceable, especially if there is no severability clause. 2) even if there is indemnification, remember that if the commissioner/artist cannot afford to pay these legal fees or fines, YOU still need to...and you might sue him and wait forever to get your money back(or never get it back because he has no money) while still spending money for the lawsuit to sue him... it's the concept behind "can't draw blood from a stone."

Honestly, if you worry there might be liability, a rejection is better suited.

Good luck!

Unless the client keeps you anonymous as the artist (and even that's not safe because someone can identify you by just your style) I would not take this commission. Doing something like that based on politics is opening a shitty can of worms, with backlash and can destroy your commission business.