Final answer:
The Voting Rights Act of 1965 significantly increased Black voter registration by removing discriminatory barriers. The Shelby County v. Holder Supreme Court decision in 2013 weakened the act, leading to new voting regulations in some states. As a result, voting patterns have since been influenced by these legal changes.
Step-by-step explanation:
The Voting Rights Act of 1965 brought about significant changes in voting patterns by eliminating barriers such as literacy tests that had disproportionately disqualified African American voters. The act also permitted federal examiners to enroll voters who had been denied suffrage by local officials. This resulted in a rapid increase in Black voter registration. However, in 2013, the Supreme Court case Shelby County v. Holder challenged the act, declaring that parts of it were no longer necessary, which led to new voting restrictions being implemented by some states. These changes in legislation have prompted legal challenges and a shift in voting patterns as states enacted laws concerning photo ID requirements, early voting, and voter registration processes.