Final answer:
The Supreme Court's Shelby County v. Holder decision invalidated a critical part of the Voting Rights Act of 1965, ending the preclearance requirement for certain jurisdictions with past discriminatory practices. This allowed states more freedom to change voting laws without federal oversight, which led to the implementation of restrictive voting measures in some states.
Step-by-step explanation:
The Supreme Court's ruling in Shelby County v. Holder (2013) marked a significant shift in the enforcement of the Voting Rights Act of 1965. This landmark decision effectively dismantled a key provision of the Act that required certain states and local governments with a history of discrimination to obtain federal pre-approval, or preclearance, before they could implement any changes to their voting laws or practices. The 5-4 decision stated that the coverage formula used to determine which jurisdictions were subject to preclearance was outdated and violated the Tenth Amendment which enshrines states' rights. Consequently, various jurisdictions immediately began to enact identification requirements and other restrictions on voting, which have been subject to legal challenges ever since.
The decision was met with opposing views; some saw it as a victory for states' rights, while others perceived it as a regression in civil rights achievements. The majority opinion declared that the previous preclearance conditions were no longer responsive to current needs and overreached into the domain of state sovereignty. As a result, states previously covered by the VRA were no longer required to seek federal approval to change voting laws, leading many of them to pass legislations that potentially limited voter access. The ruling has since influenced subsequent legal battles and legislation regarding voter identification laws and access to voting.