The problem with distinguishing agents provocateur from real terrorists lies in the proof. Enough real terrorists / revolutionaries / gangsters exist that one cannot assume governments acting as the sole generator. And reasonable people do not - or at least should not - act solely on suspicion.
Leakers might provide a solution, but a lot of conspiracies are very small and tightly-bound. And one cannot discount the possibility of the leak - or the leaker, e.g. Snowden - being discredited.
I would also add that the decentralized command-and-control model of terrorist organizations (i.e. cells) allows outside organizations to hijack cells for their own ends, at least temporarily. With no higher-ups actually giving orders, who can really determine the source of a particular objective?
Leakers might provide a solution, but a lot of conspiracies are very small and tightly-bound. And one cannot discount the possibility of the leak - or the leaker, e.g. Snowden - being discredited.
I would also add that the decentralized command-and-control model of terrorist organizations (i.e. cells) allows outside organizations to hijack cells for their own ends, at least temporarily. With no higher-ups actually giving orders, who can really determine the source of a particular objective?