“The people of Arizona turned to the initiative to curb the practice of gerrymandering and, thereby, to ensure that Members of Congress would have “an habitual recollection of their dependence on the people.” In so acting, Arizona voters sought to restore “the core principle of republican government,” namely, “that the voters should choose their representatives, not the other way around.” The Elections Clause does not hinder that endeavor.”

“Independent commissions offer several benefits, including eliminating the appearance of impropriety and making elections fairer. Legislators, for instance, are four times more likely than independent commissions to create congressional districts that ‘deny voters choice in the primary’ and two times more likely to do so for general elections. This is perhaps one of the reasons why maps drawn by independent commissions face fewer legal challenges than maps drawn by politicians.”