Three Supreme Court justices are registered Democrats and two or three are likely registered Republicans, according to a new analysis released today by Fix the Court. At a time when justices’ associations are coming under greater scrutiny, the nonpartisan judicial watchdog is calling on the justices to renounce their party affiliations.

“Supreme Court justices are supposed to be apolitical arbiters of cases and controversies who are above partisan politics,” FTC executive director Gabe Roth said. “But the formal and public affiliation between justices and political parties calls that independence into question.”

The counsel to the Montgomery Co., Md., Board of Elections confirmed to FTC earlier this month that Chief Justice John Roberts, wife Jane Roberts and Justice Brett Kavanaugh are “confidential voters,” meaning their registration data may remain private, and it’s unclear if they’ve indicated a party. Kavanaugh’s wife Ashley, though, is a non-confidential registered Republican.

FTC found that Justices Ruth Bader Ginsburg, Stephen Breyer and Elena Kagan are all registered Democrats, in either Washington., D.C. (Ginsburg and Kagan), or Cambridge, Mass. (Breyer). Justice Sotomayor is a registered New York voter but did not enroll with a party.

Meanwhile, FTC learned Justice Neil Gorsuch was a registered Republican during the decade he voted in Boulder Co., Colo., and retired Justice David Souter, who moved from one New Hampshire town to another in 2009, has maintained his Republican registration. On Feb. 11, Souter will be the first justice, active or retired, eligible to cast a ballot in a 2020 primary.

FTC was unable to obtain the voter records of retired Justice Anthony Kennedy, Justices Clarence Thomas and Sam Alito due to prohibition on accessing voter data in Virginia, which is where it is believed all four maintain residences. FTC was told by a Virginia official that the organization did not fall into one of the seven categories of individuals or groups able to obtain voter records under state law.  FTC was also unable to obtain the Arizona voter data for retired Justice Sandra Day O’Connor.

The takeaway: “The justices would do well to follow the lead of Justice Sotomayor and not register with either party, even though such a decision could render one ineligible to vote in a primary, as it does for her,” Roth added.

In Massachusetts, Breyer could continue voting in either party’s primary without being registered as a Democrat, and the same goes for the four likely Virginia voters at SCOTUS, though the state canceled this year’s Republican primary. In D.C., Ginsburg and Kagan would be unable to vote in a primary without registering with a party, but that would be preferable to publicly aligning themselves with one party.

Today’s revelations also raise acute safety concerns for the court, with voter records often revealing justices’ home addresses. Without an option to register as a “confidential voter” in most states at present, the court should consider working with justices’ county or state boards of elections to permit confidential registrations.

This research was inspired by a 2008 Washington Post story.