A DePaul University professor has charged Frankfurter Professor of Law Alan M. Dershowitz with committing plagiarism in his recent bestselling book The Case for Israel—an accusation that has set off a furious back-and-forth about what does and does not constitute plagiarism.

Norman G. Finkelstein first accused Dershowitz of plagiarism last Wednesday, when both professors were on a talk show called “Democracy Now!” to debate the Israeli-Palestinian conflict. The charge has also surfaced in the October edition of The Nation, in a column called “Alan Dershowitz, Plagiarist,” which cites Finkelstein’s research.

In an interview this weekend, Finkelstein accused Dershowitz of “wholesale lifting of source material” from Joan Peters’ book, From Time Immemorial, in which she argues that Jewish settlements predated the arrival of Palestinians in what is now Israel.

Finkelstein wrote a book contesting Peters’ argument—which he dismisses as a “monumental hoax”—and says he is therefore very familiar with her text.

He said that when he read Dershowitz’s book he recognized a lot of material—more than 20 quotes cited to primary and secondary sources—which mirrored the quotes Peters selected for use in her 1984 book.

Finkelstein argues that even though Dershowitz attributes those passages to their original sources, he should not have relied so heavily on Peters’ work.

While Dershowitz acknowledged that Peters’s book was a resource he used in his research, he dismissed Finkelstein’s charge that this method of research amounts to plagiarism.

“He doesn’t charge that the quotes are untrue or inaccurate,” Dershowitz said in an interview yesterday. “This seems more like a coordinated attack on the book by people who have a strong opposition to the political and ideological issues presented in my book who are afraid to take me on with the merits.”

According to Harvard’s “Writing with Sources” manual, plagiarism “is passing off a source’s information, ideas, or words as your own by omitting to cite them; an act of lying, cheating, and stealing.” The manual suggests that a passage found quoted in another scholar’s work should be cited as “‘quoted in’ that scholar.” But it does not explicitly state how to source such a passage when one has returned to the original source to check the citation, as Dershowitz says he did.

In a statement in defense of Dershowitz, James O. Freedman—a former president of Dartmouth College and former dean of the University of Pennsylvania Law School—says that Dershowitz, “when he uses the words of others…quotes them properly.”

Freedman cites the Chicago Manual of Style as saying that “with all reuse of others’ materials, it is important to identify the original as the source.”

In his book, Dershowitz points to Finkelstein as a propagator of the notion that “Jews have exploited the Holocaust to gain sympathy for a Jewish state at the expense of the Palestinians, who bear no responsibility for Hitler’s genocide against the Jews.”

Finkelstein declined to comment on his response to the case Dershowitz laid out in the book, but said his bone of contention is more scholarly—he speculates that the Harvard Law School (HLS) professor didn’t do his own research.

Finkelstein said that borrowing citations from Peters’ book is worse than borrowing from others because, he asserts, the book is biased and unreliable. “He not only plagiarized, but he plagiarized from a certifiable hoax.”

As an example, Finkelstein points to a Mark Twain quotation from Innocents Abroad used in both Peters’s book and Dershowitz’s book.