Restatement (Second) of Torts
§ 21. Assault
(1) An actor is subject to liability to another for assault if
(a) he acts intending to cause a harmful or offensive contact with the person of the other or a third person, or an imminent apprehension of such a contact, and
(b) the other is thereby put in such imminent apprehension.
(2) An action which is not done with the intention stated in Subsection (1, a) does not make the actor liable to the other for an apprehension caused thereby although the act involves an unreasonable risk of causing it and, therefore, would be negligent or reckless if the risk threatened bodily harm.