Of course, there does need to be a distinction between an actual conspiracy and a conspiracy theory.
Most often, conspiracy theories are just that - conspiracy theories. And there's a reason why: no conclusive evidence.
But now that I think about it, there have been a couple of exceptions. But those were just lacking in evidence at the beginning waiting to be discovered ... not like in the case of those nutty conspiracy theories that go around today (which are actually contradicted by actual evidence).