Your question seems more oriented towards recent history than ancient history, so suggesting something for recent history: Follow the money. In most if not all armed conflicts, there are some entities making a killing in monetary terms or terms of political power or possession over material wealth (example: mines), who have a solid incentive to make that conflict carry on or spiral out of control and who might even commit actions to ensure that conflict resolution doesn't happen. And, in some cases, who might even mastermind the conflict-sparking incident to begin with. Qui bono : Who ultimately benefited from the events that took place?
One prime example : terrorist attacks that help the ruling regime divert attention away from their own shortcomings and which galvanize loyalty for the leader of that regime, which push the people into approving undemocratic legislations, decisions which otherwise would never have been accepted. Following which, the side that the terrorists were claiming to have attacked on behalf of, gets clobbered mercilessly and ends up in a much worse state, and the resources that were under their domain are now property of the other. With these kinds of events repeating regularly and with a fairly logical and predictable sorry outcome for the side whom the terrorists represent, it's worth asking if those terrorists were genuinely representing them at all, or were they acting at the behest of the leadership or behind-the-curtain controllers of the aggravated side to justify the next actions that would otherwise never have been approved.
So, here it can become vital to trace the sources of funding involved in the incidents, who is supplying the non-state actors with arms, logistics, who allowed them to get within striking range, which safeguards that would have prevented the attacks failed and were they deliberately failed, did the people in charge at the time get punished for their failure to thwart the attack, etc.
