While Roberts indicated he has authorized the marshal of the Supreme Court to investigate the breach of Justice Samuel Alito’s draft opinion, he offered no details about how the inquiry would proceed. What’s even less clear is whether the probe will include a criminal element. While Republicans called for federal prosecutors and the FBI to get involved, many legal experts said the disclosure, no matter how shocking, was unlikely to amount to a crime. Government leaks are rarely prosecuted, with the exception of unauthorized disclosures of classified information. The culprit would be likelier to face professional consequences, such as firing and disbarment rather than prosecution, they say.

    In the meantime, the most urgent question is who will conduct the investigation. Roberts appointed the current marshal, Gail Curley, last year. She oversees a staff of 260 court employees, which includes the court’s police force, tasked with protecting the justices and grounds. But that internal police force has limited investigative capability. It’s primarily geared toward overseeing operations within the Supreme Court building and providing physical security for justices, employees and visitors.

    Curley could request assistance from the FBI, which has the resources to aid any internal probe. But that step itself would depend on how deeply the justices want another branch’s investigators poking around into their private communications.

    Some GOP lawmakers have already urged the FBI to get involved and interview anyone who likely had access to the draft. Senior Republicans on the House Oversight Committee wrote to Attorney General Merrick Garland on Tuesday seeking answers on “all potential laws violated by leaking a draft Supreme Court opinion during deliberations with the intent to threaten or intimidate members of the Court.” And former Attorney General William Barr told an interviewer Tuesday it may take a “grand jury” to identify the source of the breach.

    “It could be obstructing the administration of justice, the due process of justice,” he said on SiriusXM’s “The Megyn Kelly Show.”

    Barr also floated the prospect that Roberts could appoint a former U.S. attorney or criminal law expert to lead a special internal investigation.

    But any significant Justice Department involvement would involve problems with the constitutional separation of powers, raising the uncomfortable prospect of an executive branch agency rifling through the communications of Supreme Court justices and their closest aides.

    The scope of the Roberts-authorized investigation is unknown. A probe of the small and clubby staff of the Supreme Court would put every justice in an uncomfortable position, exposing them to questions about their phone and email records in ways that justices are rarely, if ever, confronted. And any thorough investigation is likely to also sweep up the families and close associates of justices and clerks.

    “If there’s a serious investigation of who leaked, am I right that it likely includes not only all the clerks and Court staff that would have access to the opinion, but also the Justices and their families?” wondered Orin Kerr, a law professor who has argued before the Supreme Court. “Could be pretty wide-ranging.”

    Some legal experts noted that the circumstances surrounding the draft opinion’s disclosure — such as whether any money changed hands — would determine whether a criminal predicate exists. A spokesperson for POLITICO emphasized that the company did not and would not pay to obtain the document.

    “POLITICO doesn’t pay for information or sources,” said spokesperson Brad Dayspring.

    The discussion of a potential crime was the subject of debate among lawmakers Tuesday morning during a Senate Judiciary subcommittee hearing. When Sen. John Kennedy (R-La.) suggested that the DOJ explore the disclosure of the draft opinion Tuesday, Sen. Sheldon Whitehouse (D-R.I.) shot back that it was unclear what potential crime the department would be investigating.