WASHINGTON — The Supreme Court’s internal investigation into who leaked a draft of the opinion last year overturning the landmark decision that had established a constitutional right to abortion included talking to all nine justices, the marshal of the court said on Friday.
But the justices — unlike dozens of law clerks and permanent employees of the court — were not made to sign sworn affidavits attesting that they had not been involved in the leak of the draft opinion overruling Roe v. Wade and that they knew nothing about it.
The clarification by the marshal, Gail A. Curley, who oversaw the inquiry, followed widespread speculation over its scope and limitations. In a 20-page report on Thursday, Ms. Curley disclosed that the investigation had not turned up the source of the leak while leaving ambiguous whether it had extended to interviewing the justices themselves.
“During the course of the investigation, I spoke with each of the justices, several on multiple occasions,” Ms. Curley said on Friday. “The justices actively cooperated in this iterative process, asking questions and answering mine.”
She added: “I followed up on all credible leads, none of which implicated the justices or their spouses. On this basis, I did not believe that it was necessary to ask the justices to sign sworn affidavits.”
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Ms. Curley did not indicate whether she searched the justices’ court-issued electronic devices and asked them to turn over personal devices and cellphone records, as she did with other personnel. She also did not address whether she had interviewed any of the justices’ spouses, another question that arose after her report was made public.
In releasing the report on Thursday, the court also issued a statement from Michael Chertoff, a former prosecutor, judge and secretary of homeland security, who said he had reviewed the investigation and found it comprehensive.
Mr. Chertoff said that Ms. Curley and her team had undertaken “a thorough investigation,” and that he could not “identify any additional useful investigative measures.” Mr. Chertoff declined to comment on Thursday and again on Friday, referring questions to the court’s press office.
In May, Politico published the draft opinion in the case, Dobbs v. Jackson Women’s Health Organization, in an extraordinary breach of the court’s secrecy. The final opinion, which the court issued in late June, was essentially unchanged.
Soon after the leak, Chief Justice John G. Roberts Jr. confirmed its authenticity and called the disclosure “a singular and egregious breach,” ordering an investigation. Justice Clarence Thomas likened it to infidelity, and Justice Samuel A. Alito Jr., the author of the opinion, said the disclosure endangered the lives of the justices in the majority.
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The leak also prompted wildly divergent theories. Some insisted that a liberal justice or clerk, angered by the coming decision, was the culprit. Others wondered whether a conservative leaked the draft opinion to lock in the five justices who had tentatively voted in the majority. Doing so could ensure that any wavering justice would be less inclined to change his or her mind.
In her report, Ms. Curley suggested that the investigation had pursued both possibilities, including scrutinizing clerks who had been the subject of online speculation. But the report indicated that no evidence supported those suspicions.
While the report also cited technical limitations in the court’s electronic communications, it said investigators did not believe that outside hackers were behind the unauthorized disclosure.
“It is unlikely that the public disclosure was caused by a hack of the court’s I.T. systems,” the report said. “The court’s I.T. department did not find any indications of a hack but continues to monitor and audit the system for any indicators of compromise or intrusion into the court’s I.T. infrastructure.”
