John Walsh and unintentional plagiarism
Within the post Why plagiarism destroyed John Walsh, but Scott DesJarlais may survive a sex scandal , one finds the text
And while he admitted to his mistakes, he said they were not intentional. Given the evidence, accepting that would have been tough for many people.
John Walsh's "unintentional" plagiarism gambit did not work in 2014, but the same ploy worked for Glenn Poshard in 2007. Of course, Poshard was not running for office, and was president of the university (during the investigation) at which the plagiarism happened earlier in time.
See IPBiz post
Poshard: unintentional plagiarism?