Harvard’s Writing With Sources manual, which is distributed to all undergraduates when they enter as freshmen, offers a crystal-clear definition of plagiarism: “passing off a source’s information, ideas, or words as your own by omitting to cite them; an act of lying, cheating, and stealing.”

But Dershowitz said guidelines in the legal profession are murkier.

He said that judges frequently rely on lawyers’ briefs and clerks’ memoranda in drafting opinions. This results in a “cultural difference” between sourcing in the legal profession and other academic disciplines, Dershowitz said.

Harvard Law School Dean Elena Kagan had not heard of the accusations against Tribe when The Crimson contacted her yesterday.

But after Kagan was referred to The Standard’s piece, she wrote in an e-mail: “The Law School takes all allegations of academic impropriety very seriously. I can’t comment further on this matter until I’ve had a full opportunity to review the relevant materials.”

—Staff writer Daniel J. Hemel can be reached at hemel@fas.harvard.edu.

—Staff writer Lauren A.E. Schuker can be reached at schuker@fas.harvard.edu.