Automatic or intelligent?
At its heart, this is a philosophical question. We like to think we're intelligent and exercising free will, and all, but get down to the neurological and biochemical level, and, well, were my punctuation decisions in this sentence driven by Ca/Na ion differentials across some greasy membranes, or were they intelligent?
My proposal for an agreed definition of AI: "It seems to do things that look to us as if it's thinking, but we have no idea why."
By this definition, Phalanx is not intelligent, any more than a bucket of water balanced over a door. Not even if you hook it up to an IFF database is it really thinking. If you know why it works the way it does, it ain't intelligent.
A truly intelligent autonomous weapon system might read the manifesto of the opposing forces, and decide to change sides.