I'm sorry, but politicians shouldn't 'be sarcastic' or 'make jokes'. You're trying to tell people you are serious and focused, not that you are a comedian.
They're not jokes. They're insults.
I have online people where there's a guy who will say all sorts of crap and then say he's 'just joking'. No, dude, you're an a$$hole. Belittling your fellow chatters is not funny, so STFU.
I need to follow up on this - people *can* be funny and tell jokes on the stump. It's the re-examination and "I was just joking, can't you take a joke?" that is so very wrong.
If your comments have to be explained or sane-washed later, then you need to either fire your speechmaker, not veer off-script, or just keep your mouth shut.