I think not said:
Yes I do believe it, if it is ever necessary. Just as it has happened in many countries throughout history. And what is a tyrannical government to you (although I share this view with you to a certain extent) to others it is not.
Yes, it has happened in many countries thoughout history, but never before has a country's executive held control of such a formidable force as the executive branch of the US holds today. Never before has an army had the mobility, or possessed such fire power as your military and law enforcement agencies do today.
Any action against your government would be brutally put down.
As to the definition of a tyrranical government, I believe it would read something like this:
*clears throat*
A government that does not represent the majority, and as a consequence, legislation and policy is driven by self-serving interests.
Incidentally, I believe that my own government is falling into this category, and so I won't vote for them...but with all of the rigged elections these days, who knows who you'll be getting for a government...