Unlike other states where state legislatures are toughening up their campaign finance laws, Arizona is doing the exact opposite. Yesterday, the Arizona state legislature passed SB 1516–a bill that guts the state’s responsibility to track and regulate ‘dark money’ that could be hidden in 501(c)3 and 501(c)4 non-profits, redefines campaign contributions and its transfer between campaigns, and further clouds who and how campaign finance laws should be enforced.

The fight over the Arizona bill, which could be signed into law as early as this week, has pitted good government activists against deep-pocketed corporate donors and political groups underwritten by the billionaire industrialists Charles and David Koch. It also spotlights a growing national debate over secret political spending, which is on pace to hit record levels in 2016.

We’ve seen already the influence that tens of millions of “dark” money from the Koch brothers have waged in Arizona. Americans for Prosperity, the 60 Plus Association–all Koch-backed groups–are among the key players who pushed for SB 1516:

Many of the Arizona officials now pushing the legislation swept into statewide office in 2014 on a wave of undisclosed spending, including the governor, the attorney general, and the secretary of state. They benefited from tens of millions in spending by “dark” money groups associated with the Koch brothers’ network of conservative donors.

The bill reflects, in part, growing GOP frustration with the Citizens Clean Elections Commission, the state regulatory body created by the clean elections law in 1998. In 2014, the commission levied a $95,000 fine against a free-market oriented political nonprofit group, the Legacy Foundation Action Fund, for failing to disclose its donors. Last summer, the commission also approved new rules that would force social welfare groups that met a certain threshold of political spending—$500 over a two-year cycle—to file as political committees and disclose their donors.

Both moves prompted Secretary of State Michele Reagan to intervene. Reagan is at the center of Arizona’s effort to restructure its campaign-finance regulations. Her own position on disclosure has changed during her career in public office. As a state legislator back in 2013, Reagan crafted legislation that would have required 501(c)(4) “social welfare” groups to disclose their donors, even though federal tax code doesn’t require such reporting. She even campaigned for secretary of state on a promise to use that position to shine a light on dark money.

But once in office, Reagan changed her tune. It probably didn’t hurt that she beat her Democratic opponent, former state attorney general Terry Goddard, with the help of a last-minute $300,000 attack-ad blitz paid for by a tax-exempt conservative group known as the 60 Plus Association, that portrayed Goddard as soft on immigration.

Reports later showed that the group had received money from American Encore, one of the secretive groups in the Koch brothers’ political network. Koch-funded groups groups also spent heavily to help elect now-Governor Doug Ducey and Attorney General Mark Brnovich, both supporters of the new bill to dismantle state campaign-finance and disclosure rules.

Reagan now says enforcing political disclosure rules is too difficult for the state.