Michael Dreeben, deputy solicitor general at the US Department of Justice. Photo by Diego M. Radzinsdhi.

Deputy U.S. Solicitor General Michael Dreeben will detour from special counsel Robert Mueller's legal team next week to argue before the U.S. Supreme Court in high-profile privacy case.

The Justice Department's top expert on criminal law cases will argue in Carpenter v. United States on Nov. 29 that police collection of cellphone data does not constitute a search of defendant Timothy Carpenter, accused of armed robbery of cellphones, and does not violate the Fourth Amendment.

Dreeben was recruited by Mueller in June to assist with the probe into Russian connections with the Trump campaign. The department made it clear from the outset that Dreeben was not working with Mueller fulltime but would continue to tend to the high court's criminal docket when he could.

A spokesman for Mueller's office issued this statement: “Michael Dreeben is working on legal issues as a counselor in the Special Counsel's Office, while retaining certain responsibilities as deputy solicitor general to ensure continuity of representation of the United States in the Supreme Court.”

With more than 100 Supreme Court arguments under his belt, Dreeben is an expert on “search and seizure” issues in the modern era, arguing in cases like Maryland v. King in 2013 on whether DNA swabs by police of criminal suspects also violated the Fourth Amendment.

The Carpenter case “could be the most important case involving privacy” in decades, National Constitution Center president Jeffrey Rosen said at a recent discussion of the case.

Elizabeth Prelogar, another lawyer in the solicitor general's office who was detailed to the Mueller team, also surfaced at a November 14 Harvard Law School discussion that included Chief Justice John Roberts Jr. Roberts was at the school to preside over the Ames Moot Court Competition.

Adam Jed, an appellate lawyer in the Justice Department's civil division who is also one of the roughly 20 lawyers in the Mueller team, argued a case before the U.S. Court of Appeals for the D.C. Circuit on November 13.

At an April 2016 event marking Dreeben's 100th argument, justices heaped praise on him as a lawyer who did not bend precedents or statutes to fit his arguments. Justice Ruth Bader Ginsburg said that when she sees Dreeben at the lectern, “I know he will tell it straight.” Smiling, Ginsburg also said there was another reason he liked Dreeben: “You have never called me Justice O'Connor!”