There's one thing that ought to be said, before one of them is elected president or drops out of the race or commits some blunder that abruptly ends his political career. Neither will regard it as a compliment, but there is remarkable similarity in this presidential campaign in the behavior of Ronald Wilson Reagan and Edward Moore Kennedy.

Reagan has been depicted, in this newspaper and by this correspondent, as being old, tired and hard of hearing. His capacity to be president has been questioned. Kennedy's character has been impeached, because of Chappaquiddick and its aftermath. So, too, have his political judgement, his speaking ability, his leadership qualities and his common sense.

What is similar, and remarkable, about Reagan and Kennedy is that they have chosen to grin and bear it, to campaign harder than ever and to meet their accusers -- the men and women of the national press -- with good humor and without complaint.

It is not a small thing. Spiro Agnew would quake with rage at the slightest manifestation of prejudice from the Eastern liberal media conspiracy he observed, invented and feared. Richard Nixon would whine and complain that he was the victim of persons whose views differed from his own. Others, still in public life, find it difficult to accept any analysis that questions their wisdom, their conduct, their motives or their abilities.

William Simon, then secretary of the Treasury, once objected to a secondhank comment in the next-to-last paragraph of a long and generally complimentary story.The comment described Simon as thin-skinned. He called the reporter, identified himself and shouted into the telephone: "I am not thin-skinned!"

Everyone to some degree is thin-skinned, of course, and especially so if the criticisms are of the magnitude of those that have been made of Reagan and Kennedy. The transition to the new journalism must have been especially difficult for Reagan, who grew up in an era when White House photographers by common consent took no waist-down pictures of a crippled president and personal things were written about politicians only if they were in the penitentiary.

I have covered every campaign of Reagan's, seeing him on bad days and good. He can become angry or distraught or confused about what has been said about him. In 1976 he used national television to denounce an account by this reporter that said that Reagan realized his campaign was on the skids and that his aides were looking for jobs elsewhere. But I have never known Reagan to hide out on his ranch and refuse to answer questions.

Nor has he treated those who reported critically about him with special disfavor. He has, on the contrary, been unfailingly courteous and responsive to his media critics, never whining about the treatment he has been given or suggesting that the liberties of the press should be curtailed. The worl one might have used in a pre-feminist age to describe Reagan is "manly." No doubt we need a better word now.

Whatever that work, it would seem to apply with equal force to Kennedy. Unlike Reagan, Kennedy is a man of the modern age who is accustomed to a personal quality in journalism. But of no one in American public life in this century have the personal criticisms been as harsh or searing as they have been of Ted Kennedy.

Maybe he has deserved them, and certainly he should have expected them, but that is another point. What is impressive about Kennedy is that he comes back on his campaign plane or bus and looks his accusers in the eye and tests wits with them -- day after day.