There are a myriad of laws being enacted across the nation concerning voter ID and what passes for a valid ID. In some jurisdictions a college ID is accepted and in others it is not. Some jurisdictions allow a gun permit as valid identification and other areas don't even accept a social security card.
The US should adopt a nationwide voter ID card, complete with picture which can be used in any voter district in any state. Further, these Voter ID cards should be able to be obtained through, but not limited to, any post office location, social security office, or court house.
This will make voter registration easy to obtain for any citizen, and end a patchwork of laws that discourage US citizens form voting.