Washington — This is a moment in Washington to recall Mark Twain's quip that reports of his demise were exaggerated. There is a considerable amount of talk now, on Capitol Hill, in the bureaucracy, and in the media, that the Reagan administration is beginning to fall apart. The reference points for this assessment include the flagging economy together with the way the President is dealing with it; growing resistance to Reagan programs from Congress, including Republicans; and the President's in-house squabbles.
This negative judgment is premature. The President still has strong public support, as evidenced in the polls. And he still is in command, although doubtless less so than during his protracted honeymoon period which may now be ending.
The President did little to bolster his position, however, by charging the press with damaging his ability to conduct foreign affairs by what he sees as inaccurate press portrayals of conflicts among his foreign advisers. He also questioned the media attention given to this story, which centered on reports of disagreements between Secretary of State Alexander Haig and the President's national security adviser, Richard Allen.
To begin with, it was Haig himself who raised the public-interest level of the story by giving credibility to the reports about in-house differences: he said that a top White House official was carrying on a ''guerrilla campaign'' to discredit him.
But, more than anything else, this presidential effort to blame the press for his problems evokes some unpleasant memories. Nixon, up until the very moment that the ''smoking-gun'' tape conversation was revealed, leaned heavily on this device to divert public attention away from himself and his problems.
Other presidents, to a much lesser degree, have sought to persuade the public to forget that the press is only the messenger - that the message of the president's conduct and performance, good or bland or bad, comes from him and his administration.
One hesitates to mention Nixon and his wily ways when talking about Ronald Reagan. Even Reagan's critics concede that he is a man who is fully secure and a square shooter.
The President is also highly political. He presses all the political buttons when he is pushing his programs. But not even his severest critics are suggesting that Reagan takes the low road. Cartoonist Herblock, while highly critical of Reagan, particularly on his Mideast policy, portrays him as a bumbling but not evil-intentioned figure. And Tip O'Neill finds Reagan delightful company even as the two argue over the President's prescription for the economy.
When asked why the President had taken on the press in this manner, a key White House aide replied:
''The President was expressing his frustrations at the time. In general, he feels he is getting a fair treatment from the press. But he was frustrated at the attention being given to these personalities, frustrated at his people talking too much!''
But would the President desist from further sniping at the press? the aide was asked. ''Yes,'' he said.
Obviously the President is finding that he has nothing to gain and much to lose by starting a feud with the media. He should come to see (and presidential associates say he really sees this point clearly, at least most of the time) that he and the media simply have different roles to play.
New York Times newsman Jonathan Friendly underscores these different roles and the continuing prospect of clashes between the President and other public officials and the press when he writes: ''. . . The larger issue is one that predates the Reagan administration and is likely to continue long after Mr. Reagan leaves office. It reflects a philosophic difference between the press, which says its duty is to the public and not the government, and public officials who believe that the press should not hinder important programs.''
Now comes David Stockman and his admitted loose talk, severely damaging his own credibility as well as that of the President's economic program. But this time Mr. Reagan is putting the blame squarely on Stockman and in no way blaming the press. Those around Reagan say he has learned his lesson.
While Mr. Reagan is in the midst of a stormy period, the prevailing view here among veteran political observers is that the President, although faltering a bit, still is riding high. But, it is felt, he must do his job and let the press do its job and avoid a confrontation with the media which, by and large, still are friendly toward him and as a person.