Jim Webb was Oliver North's classmate at Annapolis, where they had a celebrated boxing match for the 147-pound championship of the brigade. North won. Webb hates to lose -- fights, wars or budget battles. That is why he resigned in protest after less than a year as secretary of the Navy.

Departing, he enfiladed Secretary of Defense Frank Carlucci with scathing words to protest the Navy's $12 billion contribution to the $33 billion contraction of the defense budget. To understand the controversy, begin, as in politics one must, by distinguishing the character of the actor from the quality of the action.

Webb, the warrior-novelist, is temperamentally unsuited to the culture of government. In a brilliant Esquire magazine essay on Webb and North, Robert Timberg reports that when he asked Webb why he took up writing (his first novel, ''Fields of Fire,'' in 1978 was a best seller), Webb cited a line from an Auden poem about Yeats: ''Mad Ireland hurt you into poetry.'' From his service as a Marine officer in Vietnam, Webb, now 42, carries shrapnel in his head, back, kidney, left arm and left leg. He was the man to take yonder hill. Capitol Hill is another matter. Compromise may be man's best friend; if you try to tell that to Webb, take cover.

Webb is a casualty of a conservative administration's misrule. Reagan's deficits are strangling Reagan's defense program, including the part that, as recently as Cap Weinberger's farewell ceremony, Reagan cited as a particularly glittering accomplishment -- the 600-ship Navy. That goal now goes aglimmering.

The number 600 should not be treated as a talisman, but the defense budget, and especially the Navy, should be tailored to the nature of the nation's security needs, not budgetary convenience. The Navy is especially central to recurring American controversies.

In 1794, Congress, having previously dissolved the Navy, reestablished it as an alternative to paying perpetual tribute to Barbary pirates. But President Jefferson, who decried ''the ruinous folly of a Navy,'' stopped construction, discharged every naval constructor and dismantled many ships. Flat-bottom boats in coastal water should, Jeffersonians thought, suffice for a nation insulated from the world by wide oceans.

However, in 1889, Secretary of the Navy Benjamin Tracey, who believed that ''the sea will be the future seat of empire,'' broke with past thinking in his annual report. He emphasized not coastal defense but command of the sea based on battleships capable of defeating an enemy fleet in mid-ocean. Shipbuilding was soon to become the first large link between the military and industry.

The arrival of the United States as a world power was announced with naval assets -- with the around-the-world cruise ordered by President Roosevelt in 1908-09, and the ''Big Navy Act'' of 1916 (10 battleships, 16 cruisers, 50 destroyers, 72 submarines, 14 auxilliaries, for ''a Navy second to none''). The United States edged by ship toward involvement in both world wars, by arming merchantmen in 1917 and by aggressive behavior in the North Atlantic toward German vessels -- behavior not quite compatible with neutrality.

The Navy is suited to (in John Paul Jones' words) ''go in harm's way.'' It is the most flexible instrument for the projection of power. Thus the Navy engenders suspicion among those who do not want power projected -- isolationists of the old sort, who thought America was too good for the world, and the new sort, who think the world is too good for America.

Furthermore, U.S. foreign policy in this century has generally been Eurocentric. Today the principal threat is perceived to be at the eastern end of the northern German plain, which is primarily the Army's problem. That problem is suited to the systems-analysts' delight of quantifying threats and responses -- so many tanks versus so many countering systems.

The Navy, in its substantive and symbolic roles, expresses the nation's sense of destiny, something hard to express algebraically. A battleship, off Lebanon, when fed into a computer does not compute. An aircraft carrier can be trivialized by excessively abstract analysis: it costs X dollars a day to keep it near Libya; in an operation it might deliver Y munitions, meaning a high cost per munition.

But naval assets, being movable menaces, have effects that are difficult to quantify. Things difficult to quantify are inconvenient for analysts to credit.

The evolution of the Navy exemplifies America's journey from coastal defense to global involvement. Many Americans remain unreconciled to that journey, so the Navy will remain a subject of special contention, whether or not it is presided over by a warrior like Webb.