British Observer of the Oval Office. INTERVIEW: AUTHOR HENRY BRANDON

`EUROPEANS underestimate the problems of governing this country,'' says Henry Brandon, who has written about the workings of United States presidents from FDR to Ronald Reagan for readers of the London Sunday Times. ``Whenever somebody comes from Britain or the continent to this country, I say, `You must take a flight from New York to San Francisco to get an impression of the vastness of this country.'''

But being a British subject, Mr. Brandon concedes, proved to be an advantage during his 34 years in Washington.

``A good many presidents thought they were getting a fairer deal from a foreign correspondent,'' he says. They seemed to believe that foreign journalists ``were politically more detached and, perhaps, more objective.''

As a case in point, Brandon, whose memoirs are now in print (see review) cites an interview he had with Lyndon Johnson at the height of the Vietnam war.

``Johnson saw me about three days after the Tet offensive,'' recalls Brandon. ``Virtually the entire American press had declared Tet as a defeat for the United States. We know now ... that it was equally tough [on the North Vietnamese forces].

``LBJ was looking haggard, as though he hadn't slept for several days.... He read to me the CIA report [on the battle], which was a straightforward account, which declared the battle more or less a standoff.

``He read this to me in the expectation that he would get an objective report from me, because if he had read it to an American correspondent, an American correspondent would have been influenced by the wave of negative reporting, and to me what was important was what the President said to me.''

Brandon retired from the Times in 1983 and is now a visiting scholar at the Brookings Institution in Washington, keeping active as a working journalist by writing a column for the New York Times world syndicate. He says he sees a great deal of change in the way news is reported today. ``When I traveled on the Truman campaign train [in 1948] we were about 100 [newspaper] writers and reporters and there were only two television reporters.'' Print journalists ``were still the princes of the profession,'' he says.

Today, he says, much more emphasis is placed on analyzing and interpreting news. He theorizes that straight reporting without analysis may have been part of the reason Sen. Joseph McCarthy was able to carry out his communist ``witch hunt'' without challenge for so long in the early 1950s. ``Under the `rules' of government reporting then,'' says Brandon, ``the New York Times and Washington Post would lead with a statement that `[McCarthy] says 105 communists are in the State Department.''' Readers, he suggests, were ill-served by the reporting of the statement, without background or context.

``Today,'' he points out, ``they would add in the next sentence: `But he provided no proof.'''

Though Brandon has been a close friend of presidents and other high-ranking public officials, he says this hasn't kept him from his reportorial duties.

``I will admit that about a half a dozen times I was saying to myself, `If I print this, how is it going to affect my personal relationship?' But I nevertheless was never influenced by that.''

Brandon says he's quite impressed with President Bush. ``He is one of the best-informed presidents,'' he says. ``He's a cautious, rational man. He's selected for many important jobs people who have experience in government.''

Brandon never got much inside information from Bush while the latter was serving as vice-president. Early in his first term Brandon asked Bush if he would provide, off the record, his own views ``on this and that,'' as so many other officials were doing. Bush declined, adding that ``I'm saying this not just to you, but to every other reporter, that if I told you what I think off the record or for background, it would be known around Washington within a week.''

In the end, Brandon says, it obviously was a policy that worked quite well for Bush.