Just at the time President Carter is sending the Marines into places like Guantanamo as a symbol of American "resolve," an influential congressman is mobilizing an inquiry into whether the corps is obsolete.

The Marines, said Rep. Jack Edwards (R-Ala.) in explaining his inquiry recently, "haven't made an assault landing" since the Korean War "because that kind of fighting has gone by the board.

"If we don't have amphibious landings, is that the end of the Marine Corps?" asked Edwards, ranking Republican on the House Appropriations defense subcommittee.

Edwards said he has already asked the Library of Congress to undertake an extensive study of that question, including paying military specialists to submit papers on the subject.

Once the library study and individual papers are in hand, by December, it is hoped, Edwards said he will conduct hearings in what he termed "a workshop" format rather than a congressional investigation.

"I have a totally open mind" about what the role of the Marine Corps should be in the future, said Edwards, adding: I doubt anybody could convince me we could do without any Marine Corps at all.

"I see this as a stimulative kind of project," not an attempt by Congress to write a new charter for the corps, continued Edwards, who served two tours as an enlisted Marine between 1948 and 1951.

Impetus for the Marines study, Edwards said, came from a still-secret General Accounting Office report on the corps and his own conclusion, drawn from this year's Home budget hearings, that the mission of the Navy is changing.

GAO, an investigating arm of Congress, said in the unclassified summary of its secret report that it is "uncertain" whether Marine amphibious task forces could survive against modern weapons.

Navy and Marine leaders commanding the recent amphibious landings on Guantanamo acknowledged that their task force of three amphibious ships could not have withstood an attack since no warships had been assigned to protect them.

Edwards said one big fight over this year's Navy shipbuilding budget was whether the Marines' request for new amphibious ships should be granted.The Pentagon's future shipbuilding plans earmark much less money for amphibious ships than the Marines contend they need.

How many ships the Navy builds, and what kind, Edwards said, will help determine what role the Marines can play in the future.

With the Pentagon planning to build only about nine ships yearly for a five-year period starting in fiscal year 1981, Edwards said, the Navy will end up with a fleet only about half as large as admirals want -- 250 ships instead of 540.

"Nobody has shown me" how the Navy can perform all its assigned missions with half the ships it planned on getting, said Edwards. "Somebody is telling me that the mission of the Navy is changing.

"Part of the answer to the question of what's the mission of the Marine Corps must be, What's the mission of the Navy?"

Edwards said that "my great hope" for the December seminar and resulting report on the corps' future to be issued in January will be to inspire a thoughful Pentagon review of the corps and penetrating questions by Congress as it reviews the military budget next year.

Edwards said members of the House will be invited to the December sessions on the corps, adding that he hopes Marine Corps Commandant Robert H. Barrow will participate.