It's assault, plain and simple. --How can you justify doing that to someone?
There are no physical consequences to being spat on by a healthy person (if they are sick and do so knowingly to infect you, that is completely different). It is an insult, a grotesque one, but an insult none the less, and should be treated as such by law.
That is not necessarily true. Commission of verbal assault can land a person in jail. http://en.wikipedia.org/wiki/Fighting_words_doctrine#United_...
The fighting words doctrine, in United States constitutional law, is a limitation to freedom of speech as granted in the First Amendment to the United States Constitution. In its 9-0 decision, Chaplinsky v. New Hampshire (1942), the U.S. Supreme Court established the doctrine and held that "insulting or 'fighting words,' those that by their very utterance inflict injury or tend to incite an immediate breach of the peace" are among the "well-defined and narrowly limited classes of speech [which] the prevention and punishment of...have never been thought to raise any constitutional problem."
the test for battery is that you harmfully or offensively touched someone or something on them
i think spitting would fall under both for most juries..