All of a sudden, it seems, the search term Plagiarism Rand Paul gets over 40 MILLION Google hits. But the charge is somewhat bogus.
Plagiarism, in my experience, is one of those charges that are meant to question someone's basic integrity. Whether true or not (and it's hard to decide; see below), the mere accusation brings stigma. I have more than once been consulted about a plagiarism charge, groundless upon investigation but meant to be part of a general moral attack. Let's throw everything against the wall and see what sticks.
The gold-standard definition of plagiarism, as we all learned in high school, is the deliberate and dishonest appropriation of another's words and ideas; it's taking credit for yourself, failing to attribute originality to others.
The definition immediately breaks down when we try to apply it.
First, there's the phenomenon of independent creation. Different people can indeed arrive at the same idea independently - and not just in art and science. How many times have you thought of an "original" idea, then read it in a magazine? More evidence: look through a book or online list of quotations on any subject. You will often find the same thing said by different people, the same idea "discovered" again and again down through the centuries.
Another source of plagiarism accusations is faulty attribution mechanics. How faulty? Nebulous quantitative judgments may come into play. A student who fails to attribute once or twice in a paper loaded with properly-attributed quotes is not necessarily guilty of plagiarism (unless what he/she fails to attribute is a truly - or even fairly - original idea). But when sources are not given for half of the quoted material...well, that's a different matter.
The frequency and pervasiveness of unattributed quoting is what seems to be plaguing Rand Paul. And rightly so. There's a cumulative effect of presenting others' good ideas and articulate words as your own. You start to seem smarter or more compelling than you are.
Not that it's necessary in this case. Paul has enough smarts and charisma - not to mention ex tempore speaking ability - that he can correct his mechanics and give others credit for their ideas. There are many ways to do this in a speech. There's no excuse for failing to do it, in either an oral presentation or written work. Unless you consider...
The public domain - that's where our shared language lives. The notion of "public domain" (roughly, "Yeah, everybody knows that - or could look it up.") has been exploding since the printing press, accelerated a millionfold by the Internet. So when is something "common knowledge" that can be stated without attribution?
One of Paul's examples that made the news was the unattributed quoting of Wikipedia material on the movie Gattica. There is nothing novel about this factual information. Any account of the movie would include it.
So Paul is allowed to use it in a speech - just don't use the same words as Wikipedia (or anybody else), because that sets off people's plagiarism alarms, even though the material itself isn't novel.
Plagiarism is nothing new. It is our modern notions of intellectual property and copyright that are recent. Early English dictionaries grew mainly by incremental plagiarism of the previous author's word list.
And it's all around us: satires/parodies, songs that borrow from other songs, stories that copy older stories, and, of course, the rampant academic cheating made possible by the Internet. Guardians of academic originality constantly develop new software to search huge numbers of documents and root out the plagiarists.
But politicians should attribute carefully and not use too many quotes, lest they seem intellectually threadbare. And they need to be on constant guard against accusations of intellectual dishonesty. There's already enough doubt about their integrity.