Co-authoring generally either happens because a writer doesn’t want to say something alone or because a writer can say it more credibly with another writer. I urge you to keep it in the second camp.
Because so often, we co-write for the first reason not the second one.
Often, writers, especially in the opinion and editorial space, recognize they’re writing persuasively, and make their case about something they believe in and have the credentials to back up. And, once that realization hits them, they subconsciously panic and send the work to a colleague with similar credentials and they talk about it and suggestions are made and a co-authored piece is born.
But, here’s a rule about co-authoring: add a co-author only when they are adding a credential or area of knowledge/expertise that is outside your own. If you’re, say, a social worker and writing an opinion piece, what the hell do you gain by adding another social worker, besides someone to shoulder potential backlash with you? But, if you’re a social worker and you co-author with, say, a therapist specializing in addiction and recovery, imagine how much richer and deeper your piece is going to be by having your two disciplines represented on the page, each boosting and furthering the other.
If you’re tempted to add a co-author with similar credentials to your own, ask yourself if you are really ready to say the thing you want to say and ready to put it out in the world… and if you are maybe adding a coauthor because you want the support in case there is backlash.
Which is fine, but it also dilutes your cred that you worked so hard to get, so consider acknowledging “potential backlash” as a possible consequence or sharing your knowledge, and allowing it to be but a consideration rather than something that stops you from saying the thing fully.