RD says it's sometimes hard for politicians and their speech writers to resist borrowing from others: the speech writers are always looking to say something that will be memorable and often appropriate other past successful such examples. Of course they can use it if they give credit to that past politician. (Does the buck have to stop with the politician?) Of course because he's responsible for anything he says publicly. What this refers to are questions of integrity and trustï¿½is this politician credible? (Is it possible politicians have just run out of original things to say?) It's very difficult to come up with original speeches. John Kennedy gave some amazing speeches, and Kennedy would quote this historical quote or another, and it gave the impression that he was a very learned man, and it made him more credible than trying to pretend that he invented this phrase himself.