I'm going to cut Senator Graham a little slack for his "joke" regarding everything starting with "al" (the word for "the" in Arabic) in the Middle East being bad. Not all jokes go over, and I think he might have been aiming for something like Mary McCarthy's famous diss on Lillian Hellman:" Every word she writes is a lie, including and and the." We can't all have McCarthy's deftness of phrase.
But I think there is a bit of danger in joking about foreign policy too broadly, precisely because people may not always understand when one is joking. It might seem temporarily "winning" to crack a joke in front of an audience whose sympathies one feels in touch with, but it can come across as being the type of clod who disdains foreign languages like Arabic "because if the King's English was good enough for Jesus..."
We are, after all, living in an age where what is said behind closed doors* can be broadcast around the world. Language matters, and sensitivity to it is a very good place for diplomacy to begin.
(And some people skip the closed doors and at once broadcast their ignorance around the world. Long story short: words mean things)