what is the theme to this poem?
When the Nazis came for the communists,

I remained silent;

I was not a communist.


When they locked up the social democrats,

I remained silent;

I was not a social democrat.


When they came for the trade unionists,

I did not speak out;

I was not a trade unionist.



When they came for the Jews,

I did not speak out;

I was not a Jew.

When they came for me,

there was no one left to speak out.