First they came for the Socialists

First they came for the Socialists,
  and I did not speak out— Because I was not a Socialist.

 Then they came for the Trade Unionists,
  and I did not speak out— Because I was not a Trade Unionist.

 Then they came for the Jews,
  and I did not speak out— Because I was not a Jew.

 Then they came for me—and there was no one left to speak for me.

 - Martin Niemoller