A government watchdog group alleges that two of the Supreme Court's most conservative members had a conflict of interest when they considered a controversial case last year that permitted corporate funds to be used directly in political campaigns.
The letter asks the department to look into whether the jurists should have disqualified themselves from hearing the campaign finance case if they had participated in a private meeting sponsored by Charles and David Koch, billionaire philanthropists who fund conservative causes.
A Supreme Court spokeswoman said late Thursday that the justices did not participate in the Koch brothers' private meeting, though Thomas "dropped by."
If it is believed there was a conflict, the Justice Department, as a party to the case, should ask the court to reconsider the decision, Common Cause said.
The landmark case, Citizens United vs. Federal Election Commission, was decided a year ago this week. It permitted corporate and union funds to be spent directly on election advertising, a practice that had previously been restricted.
The Kochs have been significant donors to independent-expenditure campaigns, which increased dramatically after the Citizens United decision.
The letter is based in part on references to Scalia and Thomas made in an invitation to a meeting this month of elite conservative leaders sponsored by the Kochs. The invitation, first obtained by the liberal blog Think Progress, names the two justices among luminaries who have attended the closed Koch meetings at unspecified dates in the past.
Representatives of the Kochs declined repeated requests for comment. The Justice Department did not immediately respond to a request for comment. Decisions about recusal from cases are up to each individual justice.
Some legal scholars dismissed the complaint as not likely to succeed. But others said raising the issue could engender useful public scrutiny and debate about judicial independence.
Stephen Gillers, a legal ethics specialist at New York University, said the Koch brothers' use of Scalia's and Thomas' names for their upcoming meeting was "troubling."
"I believe the nation has a right to know exactly what role, if any, the justices played in the Koch gatherings, including the content of any remarks they made and whether Citizens United was a subject of any gathering they attended," Gillers said. "The answers can help determine whether they were able to sit in the case and, if not, whether the result should be overturned."
In the invitation letter to a meeting this month in Palm Springs, sent on Koch Industries stationary, Charles Koch encourages attendance, saying that "twice a year our network meets to review strategies for combating the multitude of public policies that threaten to destroy America as we know it."
Supreme Court spokeswoman Kathy Arberg said that in the past Thomas and Scalia traveled to Indian Wells to address a Federalist Society dinner sponsored by Charles and Elizabeth Koch but did not actively participate in the separate Koch strategy and policy meetings. Scalia spoke about international law at the January 2007 meeting of the quasi-academic Federalist Society and did not attend the separate Koch meeting, she said.
Thomas spoke to the group at the same location in January 2008 about his recently published book. Thomas then swung by one of the separate Koch sessions. "It was a brief drop-by," Arberg said. "He was not a participant."
It is common for members of the federal judiciary to attend events where legal and political issues are discussed. But the law prohibits them from taking part in cases where their impartiality might reasonably be questioned. In its letter to the Justice Department, Common Cause says that such a conflict appears to exist.