On Jan. 7, Jay Jorgensen took an unusual call from his former boss, Supreme Court Justice Samuel Alito Jr.

Alito's request: Would Jorgensen have time to argue a Supreme Courtcase in April -- a case Jorgensen had never heard of -- for free?

In Greenlaw v. United States,it seems the government had decided that it agreed with plaintiffMichael Greenlaw on the main sentencing-related issue in the case. Sothe Court needed someone else to argue against lawyers for Greenlaw, aMinneapolis drug dealer.

Jorgensen, a partner with Sidley Austin, eagerly agreed to theinvitation, and on Tuesday he will make his debut before the highcourt. In doing so, he follows a little-known and rarely availablepathway that has launched the Supreme Court appellate careers ofseveral former high court clerks. Among them: John Roberts Jr., nowchief justice, and Maureen Mahoney, who heads the appellate andconstitutional practice at Latham & Watkins.

Even more rare is the fact that Jorgensen won't be the only lawyerarguing as an appointed counsel under these circumstances on Tuesday.In a separate sentencing case called Irizarry v. United States,Catholic University law professor Peter "Bo" Rutledge, a formerClarence Thomas clerk, will also be appearing as "amicus curiae insupport of the judgment below," as the Court phrases it. This will alsobe Rutledge's first time before the Court.