HOW SATISFYING it was to see Mr. Carter holding a press conference in Warsaw yesterday. A press conference is, after all, as American as apple pie: It is one of the principal devices by which a politican holds himself accountable to the people. It is only out of misplaced deference that, in any one-party state with a controlled press, a visiting President submits to local practice, thereby in some measure legitimizing it. Mr. Carter did well especially to publicly promise written answers to dissident Polish questioners whom the Polish government had excluded from the hall. We regret only that the government, after granting him the occasion, did not feel confident enoughto present the news conference live to the Polish people - though, in fairness, it was broadcast in full with only one detectable change, later in the evening.

Mr. Carter surely knew that, from American journalists, he could expect questions that would tax the discretion if not the graciousness befitting a President on a diplomatic mission. He got such a questions, and he handled them nicely. He did not rub in the fact of the Soviet Union's strategic domination of Poland, or the fact of Poland careful effort to lengthen its domestic leash, but he did give the Poles due credit for the human-rights level to which their history and politics have brought them, and he did so States is quietly keeping the pressure on.

This was Jimmy Carter's first trip to Eastern Europe and, as one might expect from a President whose National Security Adviser believes in "building bridges" to Eastern Europe, he appealed strongly to local nationalism. In his visit to national shrines and his wife's audience with Cardinal Wyszynski, in the flattering tone of many of his remarks and his acceptance of First Secretary Edward Gierek as a worthy international interlocutor, in his provision of extra credits by which Mr. Gierek can buy grain to Carter demonstrated a special respect for Poland and, by extension, for other Soviet-bloc countries prepared to step out on their own national paths.

A succession of American Presidentshas wished to demonstrate, for domestic political reasons as well as strategic one, that Eastern Europe does not fall within an exclusive Soviet sphere of influence. This is a perfectly proper and useful goal as long as due respect is given to what has been called "the Soviet tank factor." Poland is an occupied country, and so are most others in Eastern Europe. Within these limits, however, the United States can make a modest but not negligible contribution to liberation and to the easing of the conditions of life of the people. It can do this by holding up realistic human-rights standards, by encouraging the governments of the region in their pursuit of their own national traditions, and by providing them openings to expand their political, economic and cultural with the West.