There is a terrific statement by pastor Martin Niemoller (from wikipedia) about the Nazi rise to power and the purging of their chosen targets, group after group.
First they came for the communists,
and I didn't speak out because I wasn't a communist.
Then they came for the trade unionists,
and I didn't speak out because I wasn't a trade unionist.
Then they came for the Jews,
and I didn't speak out because I wasn't a Jew.
Then they came for me
and there was no one left to speak out for me.
