Here is an sports analogy I really like that makes sense of this question:

You become a winner not on the playing field but on the practice field. No matter how hard you try and no matter how much desire you have win, it means nothing if you only do it on game day.

Back to the original question…If you love your country you will do much more than just “not vote”. If you are upset with the party system, fight it before the election. Volunteer for the libertarian party, etc, but do it before election day and do it before the election year.

If you really have no opinion and don’t care to form one, then don’t vote. But if you think McCain will help this country more than Obama (or vice versa) and you don’t vote just to prove a point, then you are definitely unpatriotic. You are too lazy to try spend some the time and do some work to change the system so instead you decide to sit at home and detach yourself from your country.