Yet Roberts’s record has demonstrated that such concerns rarely seem persuasive enough to tilt him against the GOP’s preferred position in cases that revolve around the basic rules of democracy and elections. (The one big exception to his partisan pattern on election-related cases was his joining in the 2019 ruling rejecting Donald Trump’s effort to add a citizenship question to the census.)

In many ways, Roberts’s hand has done the most to sketch the electoral landscape now coming into view, with voting rights between red states and blue states diverging more and more, and the federal government hobbled in its ability to set a common national floor of rights that applies in every state.

The one force that was best positioned to resist Roberts’s zealous vision was the ability of Congress and a president to sign new laws reasserting federal voting protections. And now Manchin and Sinema, combined with the impenetrable Senate Republican opposition, have blocked that route—possibly for years. Without federal legislation restoring a baseline set of national voting rights, “it’s hard to imagine the political process delivering any sense of fairness that represents the will of the majority,” Nelson said. “I think the ramifications will endure for generations. It is truly that consequential.”

With crucial help from Manchin and Sinema, Roberts’s triumph now appears complete. And that could trigger a decade of struggle over access to the ballot, unmatched since the days of Jim Crow segregation.