I in no way claim to know the answer. If I did I would run for President. As I mentioned its a completely different level of problem when Russia gets involved. However not knowing the answer and being able to identify an obvious failure by Obama are completely different things.
I can tell you this, Obama was correct for noting that he did not start the wars in Iraq / Afghanistan that he was forced to deal with. He SUCKED for crying about it for years when he knowingly signed up for the job. Trump similarly is right to note that Obama totally screwed up Syria. Trump is now President and he must develop a plan to deal with the mess he signed up for. It is not ok to spend the next few years crying about how Obama screwed it up and have no plan.
Also anyone who tries to blame Syria on Trump after 4 months as President is completely disconnected with reality.