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.