Man you guys are LUCKY you don't have to vote. We get fined $200 if we fail to turn up to the booths on voting day, it's bullshit.
It also forces people who have no politucal knowledge or reasoning to put in their uneducated opinions. The major difference between US and Australia is that your voting public is generally very interested in politics, here they have no idea.
I once overheard a girl in her mid-20s at a coffee shop say she was going to vote for the opposition leader because "he has a cute haircut".
I think people should have to obtain a licence to vote by demonstrating some basic level of knowledge in politics. Also, the whole world should be able to vote in the US elections because it really affects the rest of the world pretty significantly.