In a ground floor office under a freeway on the Georgetown waterfront, with a small staff and a few outside consultants, independent presidential candidate John Anderson has been quietly assembling his own campaign "platform."

Scheduled for unveiling within the next few days, it looks likely, if nothing else, to sharpen the debate in this fall's presidential campaign -- and perhaps even to enrich its intellectual content.

Not that the Anderson papers will necessarily have better answers. The point is that, while all three principal candidates profess to have been in some way "born again," only candidate Anderson can be said to have been born more or less free. That is to say, free of delegates, party pressures open platform hearings, debilitating platform fights. And hence, presumably, free of the need to kowtow to regional or special interests, to warring party factions, to single-issue groups.

"We are trying to distill priorities, to articulate the national interest, rather than respond to narrow interests, as a coherent whole," says Alton Fry, Anderson's principal "issues" man, who is on leave from his position as the Washington director and senior fellow of the Council on Foreign Relations.

Among Fry's helpers, as consultants, are Robert Bowie, former deputy director of the CIA and once head of policy planning at the State Department under President Eisenhower; Harvard professor Tom Schelling; J. Robert Shaetzel, who was Lydon Johnson's and Richard Nixon's ambassador to the European Economic Community; Nathaniel Samuels, undersecretary of state for economic affairs in the Nixon years.

Part of their mission is to produce a book-length compendium of "position papers" on defense, foreign policy, the economy, social welfare -- the usual platform planks. But much the most intereting part is an effort to boil all this down to a 10,000-to-15,000-word manifesto that would attempt to relate -- and reconcile -- in a realistic and rational way the commands of national security abroad with the imperatives of economic vitality and social stability at home.

It's hardly a novel concept. Every presidential candidate begins with the premise that foreign and domestic policies are indivisible. You know the litany: We must set our own house in order . . . Economic strength and social justice are essential to our national security . . . We must lead by the example we set to the rest of the world. And you also know that the exigencies of delegate-hunting and party "unity," not to mention vote-getting, almost invariably produce entirely unreconcilable promises of lower taxes, more jobs, controlled inflation and higher spending for social welfare and defense.

John Anderson may wind up doing the same. But just because not quite the same set of pressures is working on him, his "platform" has a higher chance of offering a relatively pure test of what it would be like if presidential candidates really did apply the one-big-ball-of-wax theory of foreign and domestic policy that is so dear to the hearts of political scientists.

Illustratively, the Anderson platform writers point to the Persian Gulf. Their man, they say, accepts the need to deter Soviet expansion, to secure access to the oil and, accordingly, to establish a more impressive U.S. military presence in that part of the world.

But exactly how much military effort Anderson would make to guarantee the uninterrupted flow of Arab oil would be tightly connected to domestic oil conservation and the development of alternative energy sources. The much-trumpeted 50-cent-per-gallon tax on gasoline at the pump to discourage consumption is thought of as an integral part of Anderson's foreign policy.

Similarly, when Anderson thinks of bigger U.S. defense spending, he also thinks of tax reform, which, in a real sense, is his key to everything. He's for something more than Jimmy Carter's 3 percent real growth in annual defense spending, but he wouldn't put a flat figure on how much more.

He would shelve the MX, but consider alternatives; expand the Navy from 450 to 600 ships; substantially increase conventional forces; aim for nuclear parity, not superiority.

But precisely how much he would spend for defense, and how fast, would be "modulated," as Fry puts it, to the state of the economy. And the economy would be dealt with, largely, by a "far more sensitive use of tax powers" to discourage price/wage increases, encourage productivity, promote industrial research and development, generate jobs.

You will note more differences here with Ronald Reagan than with Jimmy Carter. Against the latter, aides say, Anderson will argue mostly that a fresh replacement is needed for a burnt-out case. This is not a program likely to race the pulse -- no giant tax cuts, no huge new defense buildup. But it should offer, at the very least, a sort of "born free" benchmark against which voters may be better able to measure the programs and the promises of the major party candidates.