Well, at least we know that Kennedy wrote Profiles In Courage all on his own. BTW, a joke I used to tell was that some folks in Boston sound so profound that even the hookers there say things like:
"Ask not what your John can do for you but what you can do for your John.
The fact is that there are very few political speeches that have not been cobbled together (plagiarized) from those that went before.
Lincoln's Gettysburg Address was an original. And Harry Truman had some great original lines -- like telling the critic who dissed his daughter's singing voice that he was an SOB.
Today, you'd be hard pressed to find original oratory anywhere. Although "I did not have sexual relations with that woman" is quite quotable.