When to give up seeking justice after you've been plagiarized? I found that a Ph.D. student, recently graduated, plagiarized over a dozen passages from a book I based on my own Ph.D. dissertation of some years ago.
Their dissertation is on the Internet, which is how I became aware of the plagiarism. I am in the US, I should say, while the student’s university is in another country (not a third-world country, as someone asked, and it is one with rules similar to those in the US about plagiarism).

In most instances the student cited me as a source at the end of sometimes long, closely paraphrased passages. I believe this still constitutes plagiarism in the form of "excessive paraphrasing."  

As UNC-Chapel Hill notes, for example:


  Even if you cite your source, paraphrasing can still be plagiarism if all you do is rearrange the author's words, delete a phrase or two, or insert a few synonyms and claim the passage as your own.


When I reported the student to their dissertation committee chairperson, nothing happened.  The chairperson did not even report the matter as required to the administration.

Dissatisfied, I took the matter to the university's director of student ethics, who told me I had a strong case not only for plagiarism, but for unprofessional conduct. The director assigned a random professor to investigate, who to my surprise absolved the student of wrongdoing. The only reason given was lack of evidence of intent to deceive.

Again dissatisfied, I took the matter to the president of the university, who agreed to hear my concern.  Once I revealed the nature of that concern, however, the president no longer responded to me. Even the president's assistant, whom the president had included in the discussion, no longer responded. 

I have been careful not to come across as a loon (between the president and his assistant, for example, I sent a mere four emails, only two of which were follow-ups saying "I haven't heard from you: can you confirm receipt?") In short, I think I have responded as any rational person might in such a situation. 

I should add I am an experienced scholar widely known in my field. (Granted, it's a narrow field.) But because I am no longer affiliated with a university, I have no one to represent me. (My publisher did contact the student formally and threaten legal action, but, again, only if the student should publish the plagiarized text.)

I was told by an attorney friend there is no point involving attorneys because there is no material loss on my part. If, however, the student publishes the dissertation as a book, then an attorney could be involved, even if the loss involved is negligible. (We aren't talking Harry Potter, after all, but obscure academic works.) 

My question is: at what point should I give up seeking justice? (I would have been content with the student merely rewriting the paraphrased material – but discussions never reached the subject of remediation. That's all I really want to achieve, and I think having been caught and having to revise the text would have been punitive enough for the student.)
As you know, there are two separate issues with plagiarism: 


Claiming ideas as one's own
Claiming words as one's own


You have a legitimate concern about the second -- if this student is going to directly use your words, he needs to use quotes. Attempts to get around this by making one or two insignificant changes are not appropriate. 

That said, I can understand why the president of the university didn't want to get involved -- as academic crimes go, this one is quite minor. I agree that the "lack of intent to deceive" ruling was erroneous, which is unfortunate; getting the student to re-write the content, with no other penalty, would have been a far more appropriate outcome. 


  At what point should I give up seeking justice? 


I think it would be appropriate to reach out to the student (I would have started here, personally), their advisor, and the university's ombudsperson (in that order), just asking them to rewrite those sections and to not do it again. If they refuse, it would probably take a lawyer to get them to listen -- but you don't have any damages (not even to your reputation), so that seems a bit excessive in this case.