It could begin by the DOJ impaneling a grand jury and calling people in under oath, with criminal charges and impeachment or forced resignation as the end point. Notably, because grand juries operate in secrecy and under special rules, they have wide scope in their questioning and little ability for those called to testify to claim immunity or otherwise refuse to appear or to answer.
As an alternative to a grand jury or in cooperation with it, the House Judiciary Committee could call Alito and his colleagues to testify publicly. That would effectively put any Justice who leaked under the threat of not just impeachment but criminal charges for perjury if they were proven to have lied under oath by denying that they had leaked or knew who the leaker was.
Alito is no fool and no doubt sees this as possible, with himself as a key witness. As with a grand jury, if asked under oath by the House Judiciary Committee, Alito and his colleagues cannot decline to answer as to whom they suspect and why.
If Trump were President and the GOP held both houses of Congress, then one or more Justices would resign if the scenario that I have outlined above were set in motion. And Alito has just told everyone that he is willing to put the ball into play.
If pressed, the result would be an upending of the Leftist bloc on the Court and in the federal judiciary at large because one of their most powerful would -- for the first time -- have been called to account for judicial misconduct. Secrets of all sorts would come spilling out about judicial misconduct on the Left because a process of reckoning would have begun.
“Alito and his colleagues cannot decline to answer as to whom they suspect and why.”
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They would just give a non-answer answer.
Its true that Alito is deeply concerned about the court but Washington is all about politics, not the truth.
While the leak is a matter of grave concern in DC maintaining power and control is above all.