The American system of government is founded on a premise of consent. The Declaration of Independence set forth that governments derive "their just powers from the consent of the governed". Abraham Lincoln said that "no man is good enough to govern another man without that other's consent". But what constitutes consent? As far as I know, none of the Founders or their intellectual descendents clearly delineated the concept of consent.
Presumably, consent must be voluntary and freely given. So behavior that is forcibly extracted from an individual (such as being taxed or drafted) does not count as consent. Similarly, it would appear that merely living within an area controlled by a government is not consent, either -- I happen to have been born and raised in the United States of America, but being born was not a voluntary act on my part and in all the years since I don't recall ever being asked if I consented to the national government headquartered in the District of Columbia. Presumably I could "vote with my feet" by moving someplace over which the U.S. government does not assert control, but since my consent was never requested I see no special reason to do so. The closest thing to granting consent is voting; even if I never vote for a winner ("he's not my president"), it could be construed that I have consented to the results simply by participating in the electoral process. Perhaps this is why government do-gooders are so adamant about the "civic duty" of voting (much more so than more productive activities such as writing to one's representatives, engaging in peaceful protests, and testifying before government committees).
Once in a while one sees a bumper sticker proclaiming "Don't Vote: It Only Encourages Them." This expresses the matter perfectly. If you don't like the policies of Starbucks, McDonalds, or some other company, you are free to not buy their products, or even to organize a boycott. Unfortunately you can't pick and choose government policies by frequenting alternative providers as you can in a free market (especially since most elections merely swap one monkey for another while the same old organ grinder keeps playing the same old tune). So it's all or nothing, and you have only one chance not to buy: by not voting.
So don't vote. It only encourages them.
Peter Saint-Andre > Journal