The US Supreme court on Monday ruled [opinion, PDF] 5-4 in Arizona State Legislature v. Arizona Independent Redistricting Commission [SCOTUSblog materials] that the Elections Clause [text] of the US Constitution permits the state of Arizona to adopt a commission to draw congressional districts. At issue was a proposition [materials] passed by Arizona voters that created a special commission to draw congressional districts, a role that had traditionally been filled by the state legislature. The legislature challenged the legitimacy of the board, but writing for the court, Justice Ruth Bader Ginsburg said that not only was the commission permissible under the Elections Clause, but that the Arizona state legislature lacked standing to challenge it. The ruling upheld and earlier decision [opinion] by the US District Court for the District of Arizona.
Chief Justice John Roberts wrote a dissent, as did Justices Antonin Scalia and Clarence Thomas. The court granted certiorari to the case in October and heard oral arguments [JURIST reports] in March.