The Elections Clause of the federal constitution provides, "The Times, Places and Manner of holding Elections for Senators and Representatives, shall be prescribed in each State by the Legislature thereof." (emphasis added). Because the independent redistrict commission was created by voters through ballot initiative rather than by the legislature, the constitutionality of congressional district maps drawn by the commission was under dispute. (All agree the commission has authority to draw state district maps.) The Arizona Legislature filed suit in federal court, seeking to take back the power to draw congressional district lines. The case eventually went before the U.S. Supreme Court.
The Arizona Legislature was so confident that it would prevail in the U.S. Supreme Court that it even hired a firm to redraw the congressional district maps without waiting for the Court to make its decision.[28]
On June 29, 2015, the U.S. Supreme Court rejected the legislature's argument in Arizona State Legislature v. Arizona Independent Redistricting Commission.[29] The Court held the term "legislature" in the Elections Clause could be read broadly to mean "the power that makes laws," not just the two representative houses. Because Arizona Constitution granted voters exactly "the power that makes laws," the voters were not prohibited from adopting laws governing redistricting.[30]
The court's decision left intact the independent redistricting commission's full authority, and implicitly upheld similar commissions in other states, notably the California Citizens Redistricting Commission.[citation needed]
The Supreme Court upheld the 2010 redistricting in Harris v. Arizona Independent Redistricting Commission.[31]