Hm, perhaps... but all those you have listed are, and always will be, possibilities regardless of who the [P]resident is.
I think it was Regan who observed that Freedom is always, at most, one generation from extinction.
All those thing could happen, but I think it would be well after we have become a thoroughly corrupt toilet.
Many people want Obama to send his JBT’s into the streets to kick in doors and drag people out of their homes in the dead of night. Such actions would make our suffering under tyranny much shorter. Instead we have a much harder road ahead and some people don’t want to deal with it.
If O could get away with a violent takeover of this country he would do it. But he knows that his tyranny has to have an air of legitimacy.
The only way we can counter what he is doing is through an incredibly laborious effort of debate, rallies, PTA meetings, city council meetings, letters to the editor, blogs. Correspondence to Congress, Voting, phone calls, education etc.