Ian Millhiser for Vox:

The Supreme Court will hear a major case on April 26 that could fundamentally alter the Court’s approach to laws requiring political organizations to disclose their donors — a change that could make it much easier for big spenders to hide the ways they seek to influence policy and elections.

That case is Americans for Prosperity Foundation v. Rodriquez. But to fully understand it, it’s important to keep in mind the Supreme Court’s decision in Citizens United v. FEC(2010).

Citizens United is best known forits anti-canonical holding that corporations may spend unlimited money to influence elections. While five of the justices who heard Citizens United voted to dismantle much of the nation’s campaign finance laws, eight justices also voted that the government has fairly broad authority to require advocacy groups to disclose major funders of their political activity.

Disclosure requirements should be upheld, Justice Anthony Kennedy wrote for the Court, so long as there is “a ‘substantial relation’ between the disclosure requirement and a ‘sufficiently important’ governmental interest.”

A lot has changed since Citizens United tucked this pro-disclosure ruling into its broader ruling against campaign finance limits, however. Four of the eight justices who supported disclosure rules have since left the Court, and three of them were replaced by judges who are significantly more conservative than the person they replaced.

Which brings us to Americans for Prosperity Foundation. The plaintiffs in the case — which include a conservative advocacy group closely associated with the billionaire Koch brothers, and the Thomas More Law Center, a conservative law firm that claims it was formed to promote “America’s Judeo-Christian heritage” — seek to undercut pro-disclosure decisions such as Citizens United. And, with six Republican appointees on the Supreme Court, they have a very good chance of prevailing.

The specific issue in Americans for Prosperity is fairly far afield of the foundational questions about money in politics that animated Citizens United. The plaintiffs challenge a California regulation that requires charities that wish to raise tax-deductible funds in California to disclose their largest contributors to the state attorney general’s office. State regulations require the attorney general to keep this information confidential from the public, but the attorney general’s office may use it to investigate allegations of fraud by nonprofits.