A voter identification law is a law that requires some proof of identification in order to vote or receive a ballot on the day of an election. These laws are distinct from laws that require pre-registration to vote.
As of 2015, 33 states have voter ID laws in place. They very widely in their requirements, from stricter laws requiring state-issued photo IDs in some states, to basic laws that allow identification by a variety of means.
In a trend that has prompted some controversy amongst voting rights advocates, more states than ever are requiring photo ID. Twelve states now require voters to show some form of photo identification and efforts are being made in as many other states to institute similar requirements.
Many argue that voter ID laws are politically motivated: they impose a disproportionate burden on disadvantaged voters while purporting to protect against in-person voter fraud, an issue that is arguably non-existent. Additionally, many of the efforts to enact stricter voter ID laws have occurred in states that were covered by the Section 5 preclearance provisions of the Voting Rights Act prior to the 2013 decision in Shelby County v. Holder, which struck down the Section 4 coverage provisions. This cleared the way, in many respects, for states and localities with poor track records of protecting voting rights to enact voter ID laws which may have a negative effect on some populations—without federal approval.