My basic thought is that a lot of people fought and died for our right to vote. To just decide not to vote means that you A; are apathetic about who runs the country, or B; Believe those people fought and died so you could exercise your right to not vote. Personally, I believe that if you don't vote you've lost the right to complain about the result. No compulsory voting often means that you get a majority of the extremes from both sides showing up. I always thought that the US was a very politically aware nation.