While I am an ardent civil libertarian (NOT LIBERTARIAN, NO NO NO), I recognize that there are bad people in the world, and that the best way to avoid harm from them is to be so (*&(&(*ing scary that they won't mess with you.

Fanatics will, of course, but that's true across the board.

For instance, we need to look at Putin's Russia, gangster run, gangster driven, and controlled by internal extrajudicial violence added to judicial prejudice.  Were we unable to defend ourselves, we would fall victim to that, and in fact may do so anyhow due to the "will of the frightened".  Another good example is Venezuela, a country that should be first world, but that has been destroyed by crony-socialism and outright corruption to the point it will have to start over from the bottom. 

A military and good law enforcement can control the corruption, if they are permitted to do so. Of course, the military can and MUST work strictly under civilian control.