The problem is with the matching funds provision. Political candidates in Arizona were evidently unable to utilize Clean Elections matching funds in 2010. From the story:
The Goldwater Institute Scharf-Norton Center for Constitutional Litigation represented John McComish, Nancy McLain, and Tony Bouie, candidates for the Arizona Legislature whose campaigns were funded by donations from citizens, not the government. Previously, the Institute secured three rulings from U.S. District Court Judge Roslyn O. Silver that Arizona’s matching funds provision violated the First Amendment. Those rulings were overturned by the Ninth Circuit on May 21, 2010.
But on June 8, 2010, responding to an emergency request from the Goldwater Institute, the U.S. Supreme Court blocked the Ninth Circuit’s decision from taking effect and suspended Arizona’s use of matching funds for its 2010 election cycle.The 5-4 decision by SCOTUS came on June 28, 2011.