Christopher F Rufo has accused the president of Harvard of plagiarism in an effort so clumsy that his own case provides proof that he has no idea what plagiarism even is.   To use someone's ideas and build on them one must quote or paraphrase them, cite them in the text, and the citation should be accompanied with a reference that points to the original source.   In natural science it is quite often the case that people come up with the same basic idea independently.   In social science this can happen as well.  It is also the case that when describing the same concepts, one will use the same words. For example, no one needs to cite and reference Einstein when discussing the postulates of special relativity.   I am not a expert in social science but this looks like that at worst.   Which is not a problem at all.  

UPDATE: Surprising no one Harvard will not fire Claudine Gay and also investigated the allegations of plagiarism.  While they found a few instances of poor citation they cleared her of plagiarism.  
The Tweets
Further down he cites more instances of what he thinks is plagiarism.  
It looks like he found her thesis and ran it through plagiarism detection software.  The thing about such software is that it is a start, one must then look at the citations and references and use their own brain.

Why this is NOT plagiarism.
A sampling of the specific allegations.   All credit for these images goes to Chris F Rufo by the way. 

I will not pick apart each of these in detail.  This one is enough to demonstrate that the one making the allegations has no idea what the word even means.   She paraphrases, or quotes and cites them.  Plagiarism would be this.
Had she written "I found that they play less attention to local politics ...."  That's plagiarism.  Citing the work of others 

What other scholars think.

To be fair another outlet claims she plagiarized other things.  
One of the works that allegedly contains plagiarism here is this essay. Looking at the website this looks kin to a magazine newspaper or a blog.  The standards for citations in such a publication are much looser.  No one is going to look at half a page of citations for such a thing. .  I include references in my blogs in a number of ways.  Sometimes very formal, sometimes with in text links as is standard on the informal internet.  It depends on how formal the source is.  IF it is a source that is a peer reviewed publication, I will cite a full reference.   Seeing as this was a printed newsletter like item from years ago.  Those to my recollection rarely if ever had references of any kind. 

A personal example of not plagiarism. 

For example, the concepts in " A Postquantum Theory of Classical Gravity? Jonathan Oppenheim Phys. Rev. X 13, 041040 – Published 4 December 2023".  If I was a hack I would claim that the very concept of not quantizing gravity but trying to make quantum compatible with relativity instead was my idea first. (Cite as: Hontas Farmer. Fundamentals of Relativization. Authorea. June 11, 2015. DOI: 10.15200/winn.141487.76774).  His specific idea of how this would work is different enough, and as I said in the sciences, we are all studying the same phenomena so it is likely that different people will reach the same conclusion.  

Indeed, it is the best validation in theoretical physics short of direct experimental testing.   Though a citation would've been nice, I published in an obscure journal and also gave some APS talks.  At most I loosened the jar which has now been opened. 

Part of my job as a professor is to teach people what plagiarism is and is not.  Restating someone's idea with attribution is not plagiarism.  Having the same idea independently is not plagiarism.  Presenting the work of someone else as being your own work IS plagiarism. 

Plagiarism is a serious allegation.  As one will see in the original thread responses on Twitter no serious scholar, left, right, or center thinks this is plagiarism.  It simply is not plagiarism. 

Christopher F Rufo's Tweets see above. 

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Updated to note that Claudine Gay has on 1/2/2024 resigned but not because of plagiarism.   The idea that she had plagiarized became more important that if it was or was not plagiarism.  Let me put in this way IF what she did was Plagiarism then Johnathan Oppenhiem plagiarized me by taking my idea with attribution and elaborating on it.  (Which is not plagiarism people who study the same natural phenomenon are apt to come to similar conclusions.  In real hard natural science this is well known.)  The best non woke, non left, take on this was in this tweet. 
Another great take from a very pro Israel voice on Twitter.