Just after the Supreme Court’s controversial campaign finance blockbuster Citizens United v. FEC, critics and supporters of the decision predicted the high court would weigh in next on state laws providing public funding to candidates.

On Monday, the justices proved them right, reentering the fray with their decision to determine the constitutionality of an Arizona law that provides matching funds to publicly financed candidates.

Justices will hear arguments in two cases, Arizona Free Enterprise Club’s Freedom PAC v. Bennett and McComish v. Bennett, both of which contend that the law violates the First Amendment.

The Arizona law allows candidates to receive an initial outlay of taxpayer dollars, as well as additional public matching funds if they face a privately financed opponent or independent political group that out-raises or outspends them. Opponents say the additional matching funds provide publicly financed candidates with an unfair advantage and interfere with the ability of privately backed candidates and groups to deliver their messages.

The main difference between the two cases is in the identity of the petitioners. In McComish, the Goldwater Institute in Phoenix represents only privately financed candidates. In Arizona Free Enterprise Club, the libertarian Institute for Justice represents privately financed candidates and groups that make independent expenditures on behalf of candidates.

“I think the fact the Court took both cases and consolidated them reflects the fact that after Citizens United the Court recognizes that campaign finance laws shouldn’t be treating elections as the private domain of candidates,” said the Institute for Justice’s William Maurer, counsel to the Arizona Free Enterprise Club’s PAC. “These independent groups have every right to speak and have their message heard as anybody else.”

Under Arizona’s Citizens Clean Elections Act, a state candidate who agrees to accept public financing in lieu of private funds receives a base amount of public money when a campaign begins. Matching funds are triggered when a privately financed opponent — or an independent political group — spends or receives sums over the initial base amount, minus 6% for fundraising expenses. The Arizona law was adopted through a ballot initiative in 1998 and took effect in 2000.

The Supreme Court’s grant of review on Monday did not surprise those following campaign finance challenges around the country. Last June, the justices, in what many called a very aggressive or unusual step, stayed an order of the U.S. Court of Appeals for the 9th Circuit and reinstated an injunction against Arizona’s matching funds provision.

The 9th Circuit had reversed a federal district court’s January decision striking down the provision on First Amendment grounds. The Supreme Court’s counter move halted the distribution of matching funds in the middle of Arizona’s election season and after a number of candidates for state offices had made decisions to rely on public financing.

The challengers in the two Arizona cases rely heavily upon the Supreme Court’s decision in Citizens United and its 2008 ruling in Davis v. Federal Election Commission. In Citizens United, a 5-4 majority struck down the ban on corporations’ use of their general treasury funds to make independent expenditures in federal elections. In Davis, the justices invalidated the so-called “millionaire’s amendment” to federal campaign finance law. The amendment allowed opponents of self-financed candidates to accept individual contributions at three times the legal maximum if their self-financed opponents spent more than a certain amount.

The Arizona challengers contend the circuits have split on constitutionality of these matching funds provisions. The 2nd and 11th circuits, they argue, disagree with the 9th Circuit. “We don’t challenge the ability of the government to provide funding for candidates,” said Maurer. “What we’re challenging is a system by which the government provides funding but also puts its thumb on the scales to favor a publicly funded candidate. The ultimate decision about whether public financing systems are constitutional is for another day.”

The Brennan Center for Justice represents the Arizona Clean Elections Institute, an intervenor-respondent. Its pro bono counsel, Bradley Phillips of Munger, Tolles & Olson, is expected to argue in defense of the law, according to the center.

“The Arizona Clean Elections system, in effect for over a decade, helped move the state beyond egregious corruption and recurrent scandal,” said Michael Waldman, the center’s executive director, in a statement. “The trigger funds provision, a carefully considered element of this law, was upheld unanimously by the Court of Appeals. We believe this provision is constitutionally sound, and advances First Amendment values rather than burdening them. We strongly hope the Court finds this provision constitutional, and more broadly reasserts its longstanding support for voluntary public financing.”

Marcia Coyle can be contacted at mcoyle@alm.com.