maybe two. 1) war powers are specifically prescribed to the government, so it's not necessary to strawman that argument in saying that 'we the people' are not the power in this country, and 2) just because we are a better system of government, at the moment, does not mean we are not capable of dealing with tyranny on our own soil.
with regard to #1 a founding father once defined tyranny as that which the government can do, but the citizenry is prohibited from doing.
while we have a better form of government than most countries, tyranny (except locally) is not likely - local school boards are usually the worst
rather than tyranny, corruption is more likely to occur
tyranny is not likely to survive for long without the support of the voters...usually in search of security that they will eventually lose, rather like the stop and frisk in nyc
small towns are most likely to have a form of tyranny - city councils, police departments, school boards, etc.