In 1959, in Baker v. Carr, the Supreme Court said it was a violation of the Fourteenth Amendment's Equal Protection Clause to make one person's vote count less than another's. It was an attack on racist legislatures and entrenched powers who suppressed minority rights. Baker v. Carr has withstood challenge for 45 years. Conservatives, including Roberts, Alito, Thomas, Scalia (and Bork) are against its principle.
One man/one vote, more than any other Supreme Court case, dramatically changed the political landscape -- it enfranchised blacks, it stopped gerrymandering in a number of cases -- it tried to create equal votes for rural and urban voters.
Samuel Alito said in a 1985 memo he is against the principle of one man/one vote, against the most important principle of this democracy. He and Roberts agree with the dissenters in Baker v. Carr.
The minority of the Baker Court did not want to take the Baker case, saying the legislature, not the courts, were responsible for deciding apportionment cases. The Baker minority, said that under our Constitution, there is not a judicial rememdy for every political mischief, for every wrongful exercise of legislative powers.
The arcane language of the law keeps the general public (and the Senators, it seems) from seeing the past, present and future clearly. The Conservative court can roll back the law based on the question of whether a case is justiciable -- does this case present of the kind of controversy that the Court has the power to adjudicate or does the Constitution require federal courts to leave the decision of "political questions" such as apportionment to the political process.
The Court, by narrowing its docket, as the Rehnquist Court did, refused to review blatant gerrymandering cases. Since 1959, legislatures have carved up electoral districts to give themselves safe seats. The Rehnquist Court, without overruling Baker, allowed those decisions to stand.
The Roberts Court will probably not reverse Baker on the one man/one vote concept, but certainly will, on a variety of procedural grounds, end what the Rehnquist Court started -- sending Baker "to the dustbin of history."