The ... were said to protect America, but were actually intended to crush opposition to war.

Each country is required to have a set of institutions which are present there in order to make some decision while they are chasing some military, political, or economical related objective or goal. As there are different factors inside any civilization or we can say nation that makes a great impact while the countries or nations are passing through any situation.

As, there were a number of institutions and state departments inside the US who were supposed or intended to protect each citizen of the US. As the military was not supposed to fight against its own people in the southern states but happened, and very unfortunately the United State's military took greater part in fighting against the tribes and other opposition forces who had the conservative mindset. So, some times the institutions which are meant to protect and develop a nation as whole turns out to be fighting against there own inside the region. As they are assembled by a few number of individuals who are then termed as war hero's fighting against there own.