"Democracy is two wolves and a sheep deciding what's for dinner."
If you believe the system to be unfair, or broken - the only logical action to take is not to vote, because if you participate in the flawed system, you only acknowledge it - you give consent to the system to rule over you, and have no right to complain about anything the winning party does.
This is the wrong attitude as well. Civics does not end at the ballot box. The most visible example in the past year is all the online protests against SOPA and PIPA that resulted in both pieces of proposed legislation being shelved. If anything, that should give you hope that we can still effect change if we work hard to do it.
Our Constitution codifies how we will give consent to the system to rule over us and how that system will rule. The Bill of Rights gives us the right to complain about anything that anyone does.
If you believe the system to be unfair, or broken - the only logical action to take is not to vote, because if you participate in the flawed system, you only acknowledge it - you give consent to the system to rule over you, and have no right to complain about anything the winning party does.