Ron Brownstein in the Atlantic on Chief Justice Roberts’s responsibility for — even authorship of — the poor state of American democracy.

Roberts as much as anyone set in motion the events that have led to this week’s climactic Senate confrontation over voting legislation. In a series of rulings over the past 15 years, the Supreme Court, often in decisions written by Roberts himself, has consistently weakened federal oversight of voter protections and struck down federal regulations meant to reduce the influence of money in politics. Almost all of those decisions have unfolded on a strict party-line basis, with the Republican-appointed justices outvoting those appointed by Democrats.

Those decisions have had an enormous practical impact on the rules for American elections. But many voting-rights advocates say that the rulings have been equally important in sending a signal to Republican-controlled states that the Supreme Court majority is unlikely to stand in their way if they impose new restrictions on voting or extreme partisan gerrymanders in congressional and state legislative districts. . . .

Roberts has often appeared reluctant to let the Court be seen in purely partisan terms. But that instinct, as many critics have noted, has not extended to cases involving the core electoral interests of the two political parties—cases in which he’s been entirely willing to engineer sharply divided rulings that separate the justices along partisan and ideological lines. (No Democratic-appointed justice has supported any of these rulings.)