From PZ Myers at Pharyngula:
It’s not often that ideas in evolutionary theory become directly applicable to politics, but now we have a case of plagiarized errors in the Trump campaign. “Plagiarized errors” is the idea that the propagation of mistakes is often more revealing of the history of a lineage than the functional parts of an organism. The example often give is of how we can catch students cheating on a test: if two students turn in an exam with identical correct answers, it could just mean they both studied very hard and mastered the material well; if they have identical wrong answers, right down to the spelling mistakes, that tells you that someone has been slavishly copying someone else. For more examples of how the concept is actually used, check out Plagiarized Errors and Molecular Genetics by Edward Max.
The nice thing about the plagiarized error concept is that it allows one to trace the history of the error. In the recent debate, Trump made an unusual error of attribution — he quoted Kurt Eichenwald (incorrectly, as it turns out, ignoring his conclusion) and claimed that it was a quote from Sydney Blumenthal. It was an odd combination of specific errors, and that makes one wonder where Trump could have gotten the same set of mistakes. It turns out that there is only one other media source that makes the same combination of errors, misattributing Eichenwald’s words to Blumenthal, and distorting the meaning of the piece in the same strange way, and that tells us exactly what source Trump plagiarized.