During the various disarmament conferences, the submarine came in for considerable discussion. England would have liked to abolish this weapon entirely. The reason was obvious, as it constitutes a threat against her vitally necessary commerce. Other nations, with smaller fleets and unable to stand the high cost of modern big-ship construction, favored its retention, contending that the submarine is a weapon which they can afford, while not being able to build battleships. Japan declared it a defensive weapon, necessary to protect her innumerable straits and channels.
An argument proposed in favor of the submarine was that it is a defensive weapon, by means of which a weaker nation can protect its integrity against an aggressor whose surface power could not be challenged. In spite of arguments that the submarine should be abolished for humanitarian reasons, or because it is an offensive weapon, or that it cannot wage war in accordance with international law, it is probable that this type will always be retained, and that the fullest possible use of it will be made in future wars.