“But does Man have any ‘right’ to spread through the universe?
Man is what he is, a wild animal with the will to survive, and (so far) the ability, against all competition. Unless one accepts that, anything one says about morals, war, politics – you name it – is nonsense. Correct morals arise from knowing what Man is – not what do-gooders and well-meaning old Aunt Nellie would like him to be.
The universe will let us know – later – whether or not Man has any ‘right’ to expand through it.”

      Robert A. Heinlein in Starship Troopers (1959)

“A nation can survive its fools, and even the ambitious. But it cannot survive treason from within. An enemy at the gates is less formidable, for he is known and carries his banner openly. But the traitor moves amongst those within the gate freely, his sly whispers rustling through all the alleys, heard in the very halls of government itself. For the traitor appears not a traitor; he speaks in accents familiar to his victims, and he wears their face and their arguments, he appeals to the baseness that lies deep in the hearts of all men. He rots the soul of a nation, he works secretly and unknown in the night to undermine the pillars of the city, he infects the body politic so that it can no longer resist. A murderer is less to fear.”

      Marcus Tullius Cicero (43 BC)