The sinking of the Argentinian cruiser Belgrano by homing torpedoes of the British nuclear- powered submarines, and the sinking of the HMS Sheffield by air-to-surface missiles, mark the first time since World War II that warships have been sunk in combat. This has raised a serious question as to the vulnerability of ships against modern weapons. Have these systems become so advanced and deadly that ships are now obsolete? Must we ask, "Why have a Navy?"

Try to contemplate what the world would be like if the United States had not had a Navy since World War II. Would the Soviets have turned back on their delivery of deadly missiles to Cuba? Formosa would now belong to Communist China. Incidents such as Mayaguez would be common. I am sure you can think of other cases where our Navy has been a priceless instrument of foreign policy and protection.

Without a Navy as a deterrent, there would have been countless incidents where aggressive governments would have forced their will on free people, or even threatened our own freedom. Our government would have only been able to complain at the United Nations. We could not have defended our allies or our own rightful interests. We could have not transported troops or equipment outside of North America. Communism would have spread without fear of reprisal.

The Royal Navy has most recently demonstrated its importance to Great Britain in the Falklands crisis. No matter what the outcome of the war, without its navy the British could have done nothing to protect their property in response to the Argentine's aggressive invasion.

The sudden sinkings, however, have exposed the vulnerability of ships to modern weapons. While these vulnerabilities have not reduced our need for a Navy, they have affected the central matter of how we should direct the future composition of it.

Setting aside its strategic mission, our Navy's two most important missions are to: (1) defend the free world's shipping lanes and (2) project offensive power far from our island nation.

The major threat to the accomplishment of these missions are submarines and missiles, which can come from submarines. Our logical adversary is the Soviet Union, and its greatest strengths are our greatest vulnerabilities:

Defense of shipping lanes: When they operate far from their homeland, the Soviets have difficult logistics and coordination problems, and they must spread their forces thin. Our carrier battle groups and anti-submarine warfare (ASW) forces can do a good job of keeping the sealanes open between the United States and Europe, the Middle East, the Pacific and even the South Atlantic--although, the Navy is perhaps currently too small to accomplish all of these tasks at one time. But it is for this mission that we need a large anti-submarine warfare force and many more medium-sized aircraft carriers to provide air, sea and subsurface defense to convoys. This, I believe, is the mission that Sen. Gary Hart wishes to expand by increasing our carrier force from 12 to 30 in the long term, with a mix of medium-sized carriers, more affordable than the big-carrier plan.

The offense: The primary areas where the Navy would be able to project offensive power are in the Norwegian Sea, the Mediterranean Sea (including possibly the Middle East) and off the Pacific coast of the Soviet Union. It is this mission that presents the greatest threat to our present force and in which we are most vulnerable. The Soviets can amass an awesome force of nuclear-powered and conventional submarines, surface ships equipped with anti-ship (carrier) missiles, and a huge force of modern bomber aircraft, which carry an impressive array of anti-ship and carrier missiles. This foce is far more capable than that which the Royal Navy has faced.

This vulnerability is even further magnified if we consider the possibility of tactical nuclear warfare against our capital ships. That the Soviets would not resort to this option is a large assumption. The use of nuclear weapons would be devastating to our concept of carrier battle groups, and it supports a move to dispersion of forces.

The Navy's present answer is to build two more super carriers and many more supporting units, all at great cost because the big decks can withstand more attack. Placing large portions of a limited budget into a very few capital ships does not increase our offensive capability in the face of the Soviet threat.

Another alternative is the use of a Tomahawk (pilotless, long-range cruise missile) to our advantage. U.S. Navy submarines are our safest platforms from attack and have high survivability in the high-threat offensive regions. A force of nuclear-powered submarines designed to carry many Tomahawks could ostensibly provide the same offensive power as super carriers, but be far more assured of arriving.

The Spruance class destroyers can be fitted with many vertical-launch Tomahawks. These ships can be mass-produced and deployed for a fraction of the cost of a super carrier. The U.S. Navy's surface force would be more vulnerable, but could be dispersed into large numbers of ships, each with considerable offensive power. Collectively, they would cost far less than the vulnerable capital ship option.

In short, the Navy must rethink the force needed to realistically tackle major missions in the face of modern warfare. The need was there well before Argentina's cruiser and, in particular, Britain's destroyer went to the bottom. Those sinkings should have demonstrated the need to all but the willfully obtuse.