You asked what major unconstitutional action will Obama take to create a civilian uprising?
He has been setting the table since slithering into office to either create a financial crisis or terrorist attack or both in order to take advantage of the crisis. At the onset of either or both, he will send in his fedgov drones to “restore order”. I believe that is when the poop will hit the high speed prop.
As for active duty military, I really can’t see any of them taking up arms against their fellow Americans with the exception of a few officers who are political types. They might give orders, but I doubt that any of them will follow.
It will be messy.