16. You make the assumption that elections will always be fair
Personally, I've never bought into the "gotta defend ourselves against the government angle", but just for the sake of discussion:
Let's say that, in 2014, the Republicans take the Senate. In 2016 they take the White House. It's a purely Republican government.
In 2017 we receive unquestionable proof that the Republican Party colluded with Diebold to steal the elections, and that they shouldn't have control of either. Think it can't happen? There are MANY people right here on this board who suspect that elections have ALREADY been influenced to change outcomes in some races. It's idiotic to claim that it could never happen here, or that there aren't people in our government who wouldn't do this in a heartbeat if they thought they could get away with it.