2. During the 2012 Presidential Election Ron Paul won enough delegates to earn himself a chance to speak at the RNC. When he refused to use that speech to "fully endorse" Mitt Romney, the RNC changed the rules regarding the number of delegates required (raising them) and stripped Ron Paul of his right to speak.
3. During the 2012 Presidential Election members of the New Black Panther party were photograhed, in "uniform," standing in front of the doors to some polling stations in an apparent attempt to intimidate white voters.
4. Florida still hasn't figured out how to count votes.
I'd say we have a lot of problems that need to be addressed, to make the process even remotely close to fair, before we consider making it mandatory.