Why "just joking" is not a defence.
http://www.vox.com/2016/8/9/12417100/donald-trump-assassinate-hillary-clinton-joke
But in a certain sense, it doesnt really matter what Trump intended. This tweetstorm, from Dallas lawyer Jason P. Steed, explains why.
Before becoming a lawyer, Steed was an English professor. He wrote his PhD dissertation on "the social function of humor" and found something important: Jokes about socially unacceptable things arent just "jokes." They serve a function of normalizing that unacceptable thing, of telling the people who agree with you that, yes, this is an okay thing to talk about.
This, Steed explains, is why "its a joke" isnt a good defense of racist jokes. By telling the joke, the person is signaling that they think racism is an appropriate thing to express. "Just joking" is just what someone says to the people who dont appreciate hearing racist stuff it shouldnt matter any more than saying "no offense" after saying something offensive.
Likewise, Trump is signaling that assassinating Hillary Clinton and/or her Supreme Court nominees is an okay thing to talk about. Hes normalizing the unacceptable.