> The southern challenge of the voting rights act wasn't motivated by concerns of federal overreach
“Congress — if it is to divide the states — must identify those jurisdictions to be singled out on a basis that makes sense in light of current conditions. It cannot rely simply on the past,” Chief Justice John G. Roberts Jr.
> or a drive to introduce evidence-based decision-making into politics
“If Congress had started from scratch in 2006, it plainly could not have enacted the present coverage formula. It would have been irrational for Congress to distinguish between states in such a fundamental way based on 40-year-old data, when today’s statistics tell an entirely different story,” Chief Justice Roberts wrote.
Beyond singling out southern states, and deciding whether individual court cases could be sufficient rather than having special federal oversight, the core arguments made against the act was that the current data doesn't support the need for such an act in 2016.
The justices who dissented even agreed that racial discrimination was still an issue in the country. But they found this law and the arguments supporting the continuation of special federal powers over specific states to be a poor and outdated means to confront this issue.