What is the correct status code for a RESTful resource when the request method is allowed, but the action cannot be completed

Question

... due to server-side rules.

Specifically, I have comments that nest, and I am forbidding the deletion of comments with children.

So when someone requests:

DELETE /comments/5

where the 5th comment has children, I do not allow the comment to be deleted. What is the appropriate HTTP status code? I use a 405 elsewhere on the site, but that doesn't appear appropriate here. Nor is a 401 appropriate in cases where the user WOULD have rights to delete the comment (for instance if the user owns the comment), if it weren't for the children.

Answer 1

How about sending 409. It translates to The request could not be completed due to a conflict with the current state of the resource.