Some thoughts on moving from the foreign desk to the national desk of this newspaper:

1) It is, on the whole, easier to pose as an expert on foreign matters than domestic ones.

Last summer, after the fall of the shah of Iran, Somoza of Nicaragua and Idi Amin of Uganda, but before the downfall of Emperor Bokassa of the Central African Empire and the demise of Park Chung Hee of South Korea (not a good year for dictators) came the end of Franciso Macias Nguema, president of Equatorial Guinea, overthrown by his nephew, Lt. Col. Teodoro Obiang Nguema.

A tryrant if ever there was one, Macias presided for 11 ghastly years over an island sand spit off the coast of West Africa with a separate smidge on the mainland with a inhabitated by two tribes: Fangs and Bubis. American relations with the country were suspended in 1976 when our visiting ambassador extrardinary and minister plenipotentiary was denounced by the local deputy chief of protocol, who delivered what was described as a "rambling, polemical, at times almost incomprehensible" diatribe against the United States.

All that is fact, solemly recorded on page one of The Post. But suppose it were all made up. How many readers would be in a position to seriously quibble?

Fangs, Bubis, Shiites, mullahs and Pol Pot -- for all the miracles of modern technology and communication, the globe is still replete with exoitic crannies and (to us) mysterious passions. A foreign editor and his calleagues can, with some diligence, successsfully pretend to be wiser and more knowledgeable about the obscure than ordinary folks.

Not so on national.

Anyone who takes the trouble to pick up a newspaper has background, experience and, therefore, strong views on inflation, taxes and presidential politics. Try for example, posing as an oracle on Chappaquiddick. Or gas lines. Or rising prices. Where national affairs gets technical -- on the finer points, say, of nuclear power -- there are so many bona-fide know-it-alls, committee, studies and panels that journalists end up, more often than not, as conduits for someone else's views in the current debate.

All this affects the way stories get written. It seems acceptable (although it shouldn't be) for trench-coated correspondents in distant lands to employ such sturdy terms of self-certainty as "Most modern day Europeans believe. . . " or "Indeed. . . " or "Hence. . ." or "Moreover. . ." But it is clear to me already that similar stuff from Dubuque or Sioux City sounds ridiculous.

2) It is definitely easier from the vantage point of national editor to develop sympathy for the problems of the president.

Hard as it may be to organize the world, the fact is that Russians, Chinese and Iranians, never mind Fangs and Bubis, don't vote. People here do -- or at least are entitled to. Jimmy Carter is therefore besiged by more speicial interests angered over action, inaction or reaction than any one individual should reasonably be expected to bear. Whites, blacks, rich, poor, young, old, North, South -- each must have its say.

The Post national staff is also responsible for national security matters: the State Department, the Pentagon, the CIA. These concerns seem relatively antiseptic and manageable compared with the multitude of pressing domestic issues. Mistakes at home probably won't kill you the way war would. But the harassment could drive you nuts.

Big business complaints bitterly about administration economic policies -- like U.S. Steel did the other day when it closed down some outmoded plants -- and so does big labor, which, after all, lost the 13,000 jobs. Getting something through Congress, a seemingly sensible measure to control soaring hospital costs, for instance, is a major frustration, arousing, as it did in this case, the formidable forces of free-enterprise medicine.

Or consider energy legislation. Everyone knows it is essential to do something, but deciding exactly what is a nightmare. Proposals get so weighted down with the preference of groups -- from travel agents to the people who design rationing stamps -- that the effect is enervating.

Add to that a special prosecutor investigating President Carter's chief of staff on a potential felony charge; 11 Republican candidates for president and a Democratic hopeful who is heir to one of the few magical names in American poltics and no wonder Jimmy Carter looks older, wiser, sadder and skinnier than he did on the stump in 1976.

3) Word of a change in job gets around fast in Washington, especialy to the people who do mailing lists.

Within a week after moving into the new job, my mail began to change. There were more press releases from trade assoications and government agencies and fewer invitations to embassy national days and similar entertainments. Since most of those embassy shindigs come at Post deadline time and from a news standpoint are usually unproductive, I rarely went. Still, it was pleasant to have that small stack of creamy, thick cards summoning me to champagne and smiles.

Invitations to cocktails with tire manufacturers just don't have same impact. The difference is that when embassies do the wooing we prefer to call it diplomacy. But when it's folks from home, that's lobbying.