The ethics of citizenship

They say evil happens when good people turn their backs and do nothing. I see the US as a country where the citizens are caught between complacency on the one hand and dispair on the other. Abuses of the people by the system are widespread and flagrant. Yet when one speaks out, one is generally regarded as some extremist whacko or told that "you can't fight city hall." Perhaps its true that we have lost so many freedoms that an individual no longer CAN fight city hall. What is the ethical response in the face of such indifference on the part of the government and its people? Is it still possible to effect a change for the good in this country? Should one even try?