[fredhead]

I may be wrong, but I always heard that raising your hand was assault and making contact was battery.

In this case, preparing the throw the water balloon is the assault and hitting the LEO is the battery.

Justin Beiber, what a wimpy little twerp. Any other place he would be receiving Texas wedgies in the high school locker room.

[freedomwarrior998]

You are correct. Under the common law, an assault is placing someone in apprehension of an offensive contact. The offensive touching itself, is a battery.

Thus, a person who raises his hand and strikes a person, can commit both an assault and battery (provided that the person who was struck was placed in apprehension of the contact.)

Throwing a water balloon can be both an assault (if the victim was placed in apprehension of being struck) and battery (if the contact actually occurred.)

Many people on the internet don't like to apply rules like this. They would rather change the rules depending on the victim/offender status.