http://www.politicususa.com/2015/06/29/redistricting-case-supreme-court-gave-stop-gerrymandering.html
"The background of this case begins with a ballot measure in 2000. Fifty percent of the people in Arizona voted to remove redistricting power from the legislature and to establish the AIRC. The reason was simple: Arizonians were frustrated with a rigged electoral map. Initially, the AIRC didn’t do a very good job of drawing the electoral map. As noted by Miriam Wasser, Republicans had a super majority by the end of the decade because ”the number of registered Democrats was not reflected in the election results – somewhat comparable to how a presidential candidate who wins the popular vote but loses the Electoral College loses the entire election.”
After the 2010 census, a new AIRC was elected, and they chose a different set of mapping consultants. The Koch controlled Republicans were angry because they believed the new consultants were “too Democratic” in other words, fair.
In 2012, the Koch Republican controlled legislature filed a suit claiming Proposition 106 (the ballot measure to establish the AIRC) was an unconstitutional power grab by the people of Arizona. When, in February 2014, a three-judge panel ruled that the AIRC was constitutional, the Koch Republican controlled legislature appealed to the Supreme Court."