The search for the source that leaked the Roe v. Wade draft opinion intensified this week, with Supreme Court clerks being asked to hand over their personal phone records.

On May 2, Politico published a draft opinion that made public that the Supreme Court could overturn Roe v. Wade, which guarantees a federal right to abortion in the United States. The draft opinion alluded to leaving that decision up to state governments instead.

Now, Supreme Court officials are requiring law clerks to “provide cell phone records and sign affidavits,” three sources told CNN.

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CNN reported that the moves caused some clerks to consider hiring outside legal counsel.

Law clerks who work for the Supreme Court are often considered elite, with most graduating from Ivy League schools and experience in prior clerkships, per CNN.

Utah GOP Sen. Mike Lee served as a law clerk for Justice Samuel Alito early in his career. Speaking about the draft leak, Lee said during a Senate Judiciary Committee meeting last month, “Don’t threaten and intimidate the Supreme Court of the United States. And make no mistake, that was the point of this leak.”

Publication of the draft led to widespread protests across the U.S. and has prompted many states to begin to more clearly define individual state abortion law.

The Intercept identified three key areas to search for clues in the investigation of the leak — first, the document itself, with its identifying markers, page bend and staple perforations.

Second, “the environment the document circulated in.” Investigators have likely looked into doing an audit of the printer, since most modern office printers offer information about print jobs.

The third element is the person who released it. Each staff member has likely experienced intense scrutiny, so that makes the phone record requirement more noteworthy. It suggests the investigation has not yielded the source of the leak just yet.

New York Magazine compiled “A Running List of Theories About the Supreme Court Leaker,” which includes the theory that the leaker was someone from “the right to stop (Justice Brett) Kavanaugh from defecting,” as well as the theory that it was “a leak from the left to influence (Justice John) Roberts.”

The decision on the ruling will likely come sometime this summer.

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