This World War II poster is suggesting that

Responses
A freedom of speech might have its limits in times of war.freedom of speech might have its limits in times of war.
B merely talking about issues involving the war is traitorous.merely talking about issues involving the war is traitorous.
C workers in war industries should work as many shifts as possible.workers in war industries should work as many shifts as possible.
D people who talk badly of the war should be prosecuted to the fullest extent of the law.

A freedom of speech might have its limits in times of war.