Talking with @samcubarman, who brought up an interesting idea that diplomacy is probably better associated with Wisdom than Charisma.
I’ll still keep CHA (Persuasion) for bartering and smooth talking, but I might start using WIS (Persuasion) for dealing with dignitaries! #dnd I think of Charisma as force of character. Your ability to influence everyday people, be it through charm, lies, or intimidation.
But I feel like in a room full of monarchs or diplomats, experience and insight would suit you better for arguing your points, hence Wisdom!
— Justice Ramin Arman (@justicearman) July 16, 2021
There's also a place for wit!
Intelligence (Persuasion) might be good for a DM to call for when a player struggles to come up with a convincing case, representing their character's ability to pose a clever argument to get what they want or outsmart their target.
— Justice Ramin Arman (@justicearman) July 16, 2021
Feels like a toss up. Charisma for the charm of who you are. Wisdom for knowing your audience. Same argument for other social skills too. Yeah, it's definitely a bit blurry at times. Sometimes I feel like Wisdom and Intelligence could be melded into a single mind-based skill!
— Justice Ramin Arman (@justicearman) July 16, 2021
Diplomacy is multidimensional. It’s about understanding your peers/adversaries, their positions, and their objectives; and understanding yourself and your position, and pursuing your objectives in the most effective way based on your understanding of the situation. Diplomacy is not just about getting away with something, it’s also about building trust, consolidating or furthering your standing, and avoid aggravating your peers/adversaries (don’t create grudges).
If you are in a diplomatic mission, there is no single ability check to summarise the whole thing. Simply gathering intel about who’s supporting your position, who’s against, who’s on the fence, and who doesn’t care, will take careful planing and many ability checks. There isn’t even a single way to get that information, the same way there isn’t a single path to attaining your diplomatic objectives. That’s what makes diplomacy so much fun to play, different ways to do things will have different consequences. There are compromises and trade-offs at every single step.
Charisma (Persuasion) is your ability to influence others. Yes, Insight would be helpful, hence Wisdom (Insight) checks.
Use Insight for taking in information about the people you are dealing with, use Persuasion to convince them to see things your way. No need to mess with the rules.