In the Litzow article, the focus was on the use of submarines in the early 20th century to destroy merchant fleets as well as enemy ships during war. The strength of any country’s navy included, in part, the use of submarines in naval battles to diminish the fleet of any nation engaged in battle or in competition economically with other nations. According to the article, the only way to counter that situation was to increase as quickly as possible the building of new ships that would make up for the ones that were inevitably being destroyed by submarines.
In modern times, submarines can be used for both peacetime and wartime purposes. The continuing use of submarines are important during modern times because of the increase in the use of methods from airspace including satellites, drones, and other aircraft that are capable of attacking traditional battle fleets. In modern warfare, submarines can serve the purposes of providing surveillance, intercepting enemy communications as well as conveying messages between joint forces, and attacking enemy ships at sea as well as targets on land. In addition, the capabilities of the modern submarine to travel farther distances, remain deep under the sea for longer periods of time with the sailors on board in more comfortable, professional, and efficient surroundings, and to launch modern weaponry such as missiles and torpedoes demonstrate how this form of warfare has evolved.
Military strategy still places an emphasis on the superiority of the land and sea power of each fighting force, much like during the times about which Litzow wrote; the differences mainly revolve around the expanded role that the modernization of submarines and technology are able to play as opposed to when they were a more primitive, although successful, instrument of war.