http://www.economicpolicyjournal.com/2013/03/breaking-ag-holder-asserts-authority-to.html
The comment that I saw below the article made very good sense - get out while you can.
"It is possible, I suppose, to imagine an extraordinary circumstance in which it would be necessary and appropriate under the Constitution and applicable laws of the United States for the President to authorize the military to use lethal force within the territory of the United States." - Eric Holder
So what? Insurrection, terrorism, and foreign invasion are three obvious examples where lethal force might be justified.
A private defense agency might end up being even more efficient than a government at employing lethal force against aggressors.
Are you worried that the government is going to be less humane than it has in the past? Recall our history of eugenics and slavery and civil war.
I mean, foreign invasion is a big one.