What's the correct way to view idempotency in terms of HTTP DELETE?

Question

I have spent a lot of time recently reading the HTTP 1.1 specification and relating it to REST. I have found that there are two interpretations of the HTTP DELETE method in rega

Answer 1

Being idempotent does not mean that a request is not allowed to have side-effects (that's what the 'safe' property describes). It just mean that issuing the same request multiple times will not result in different or additional side-effects.

In my opinion, the subsequent DELETE request should return an error - it's still idempotent because the state of the server is that same as if only one DELETE request were made. Then again returning the 200 OK status should be OK as well - I don't think being idempotent requires the returning of an error code for the subsequent DELETE requests - it's just that returning the error status seems to make more sense to me.