Hmm... don't want to rant, don't want to rant, don't want to rant...
If things get to that point, we only have ourselves to blame. Our form of government is based on the principle that authority to govern is derived from the consent of the governed; by definition, if we end up with a dictator in power it is because we abrogated our liberties and privileges to maintain authority over those we elect to power.
If only it were that simple.
The US withdrawel from Vietnam did not occur because anonymous protesters voiced dissent from the shadows. Images of college kids shot down in cold blood, of citizens of all ages, sexes, and races tear gassed in the streets, of women and children swept away by water cannon shown nightly, repeated, on the evening news and in the newspapers and magazines, was what ultimately forced Nixon and Kissinger to change their behavior. As mysteriously romantic as it sounds, anonymous protest is largely ineffective protest. It makes the protesters feel good but doesn't have much of an effect on public opinion. And public opinion is, as they say, the fulcrum of change in government.
If the conditions you describe truely disturb you, if the prospect of living in this sort of fascist dictatorship is something you object to, then you have to accept the hazards of effective protest. They will know who you are. That's the whole point: as many people as possible have to know who you are, what your message is, what they can do, what's in store for them if they don't.
Of course, this applies to peaceful protest (the only sort I believe in.) If you're into explosive or hazardous substances then the rules are different, but then again you'll also be known far and wide too -- as a loony tune outlaw, out to destroy Mom, apple pie, and the American Way. Your odds of effecting real change that way are, in my humble opinion, nonexistant, but that's your call. I won't turn you in but I won't mix fertilizer and oil for you, either.