Must.

There may be times when we are powerless to prevent injustice, but there must never be a time when we fail to protest.  We must take sides.  Neutrality helps the oppressor, never the victim. Silence encourages the tormentor, never the tormented. Sometimes we must interfere. When human lives are endangered, when human dignity is in jeopardy, national borders and sensitivities become irrelevant. Wherever men and women are persecuted because of their race, religion, or political views, that place must - at that moment - become the center of the universe.

Elie Wiesel