The response on many bases has been a certain inventiveness. Marines tell one another than if you bury your marijuana in a plastic bag along with a container of peanut butter the dogs will never find it. Over the years, looking good and talking straight on Capitol Hill have been the Marine Corps' forte - and maybe the keys to its survival. ''The Marines are unique among the services,'' says William S. Lind, a legislative assistant for military and defense issues for Senator Gary Hart of Colorado. ''The defense traditionalists like their short hair; reformers like the fact that the corps is open to new ideas. And it doesn't cost the country all that much.'' Some of the corps' biggest boosters have always been former marines serving in Congress. Though the number of Congressmen who have spent a day in any service is steadily dwindling, the corps can still muster eight Senators and 25 Representatives. Influential personal and legislative aides are methodically cultivated. Almost anyone who wants to hop down to Camp Lejeune, headquarters of the Second Marine Division and a hotbed of interest in German and Israeli battle tactics, and spend a weekend out in the woods bouncing around on M-60 tanks is welcome.

For whatever reason, Congress nearly always comes through. One especially critical juncture for the corps came in the standing-down years immediately after World War II, when there was a rush to unify or otherwise streamline the armed services. The Marine Corps - always regarded by the Army and its friends as essentially a landing party that got out of hand - had already shrunk from a V-J Day peak of 485,833 to just over 100,000, still five times its 1939 dimensions.

A holding action by such former leathernecks as the late Senator Paul H. Douglas (a 50-year-old private at Parris Island in 1942) and Mike Mansfield, then a Representative, and the outbreak of the Korean War saved the corps from being merged outright with the Army or reduced in size to not much more than a regiment or two. Further, a law pushed through by Douglas and Mansfield mandated that the corps could never shrink below three ground divisions and three air wings; no other service has such a charter.

During the corps' most recent siege of institutional depression, Congress overrode the Defense Department's civilian brass and the Office of Management and Budget's green-eyeshade marauders from time to time to give the Marine Corps a helping hand. Such was the case with the AV-8B Harrier. The corps, which already has three squadrons of an older-model Harrier, likes the plane because with its vertical-takeoff capability it does not need a paved runway or a carrier flight deck. It can be based nearer front lines and thus can make more bombing runs in support of the grunts on the ground. The Air Force and the Navy's carrier admirals don't want anything to do with the Harrier, and that suits the Marine Corps just fine because of its experience in Korea and Vietnam, when it lost operational control of most of its aviation units.

''The corps will probably always be a bit paranoid,'' says another Congressional defense specialist. ''They've always likened themselves to Israel surrounded by Arabs.'' Sure enough, with its R.D.F. wounds barely healed, there is already talk around the Marine Corps about a possibly decisive political battle in the near future. Since the end of the Vietnam War, the Army has consistently received a smaller share of the Pentagon pie than the Navy and Air Force, but it is now moving toward creating mobile ''high tech'' combat units that in many ways resemble Marine Corps outfits. Says one analyst: ''A year or two ago it dawned on the Army that the Persian Gulf was the new kid in town. That projection of forces was the name of the game, the rationale for expanded budgets. And being tied to a heavy force in Europe wouldn't get the Army any of those new rapid-deployment dollars.''

Meanwhile, many of the corps' senior generals believe that Barrow's being passed over this year as the successor to the Air Force's Gen. David C. Jones, chairman of the Joint Chiefs of Staff, may have staved off just such a conflict.

Barrow, the pride of West Feliciana Parish, La., and the corps' 27th commandant, would have become the first marine to chair the Joint Chiefs. But instead the job went to John W. Vessey Jr, an Army general with a reputation for being as plain-spoken as Barrow.

Some of the Marine generals, whose distrust of almost anyone who is not a member of the brotherhood seems unshakeable, maintain now that maybe it is just as well. ''It might have brought harm to the Marine Corps,'' says one. ''There is a certain tolerance for us as long as there is plenty of money to go around. The bitterness might accelerate with small defense budgets at some point in the future. There is latent opposition to the Marine Corps having its own air force and a big ground force. It's true that we have friends in Congress to look after us. But the other services might say having a marine as chairman of the Joint Chiefs is too much. Then it would be the night of the long knives; the Marine Corps would suffer.''