Two weeks ago, former Deputy Defense Secretary Paul H. Nitze held a press conference on the latest strategic arms control proposal President Carter has made to the Soviet Union.

He presented a set of charts purporting to show how many missiles, bombers and nuclear warheads the United States and Soviet Union would each have left if the Carter proposals were carried out. The proposed new balance would leave this country "in deep trouble," he declare.

A few days later a high administration official held a so-calles "backgrounder" to respond to Nitze. Under the rules of the backgrounder, the high official could not be named by reporters. And this nameless high official told reporters he could not divulge the specific terms of the Carter proposals either. But reporters were assured the proposals would leave the United States and the Soviet equal.

Yesterday, still another news conference was called on the strategic arms limitation talks (SALT) proposals, this one by Sen. Gary Hart (DColo),who is a congressional adviser to the U.S. arms negotiatiors. Declaring je did not want to "leave the field to the opposition," Hart also said that the U.S. proposals would be good for the country.

But Hart, like the unnamed official before him, said he was not at liberty to disclose what was in the arms proposals, adding that he had cleared his prepared remarks with the Carter administration to make sure he was not letting out any secrets.

"Some of those who oppose a SALT II agreement - and possibly any realictic arms limitation treaty - have rushed to judgment to reveal and condemn a treaty still being fashioned," Hart said.

"Those who favor responsible strategic arms limitations cannot standidly by while the critics adopt the strategy of smothering the infant in its crib."

The proposed treaty is sound, Hart added, and will "reportedly limit both sided to equal numbers of launch vehicles" and thus force the Soviet Union to dismantle some of its land-based missiles.

However, Hart said the proposed treaty is till a long ways from being final and would not be submitted to the Senate in any event until next year.

"Any discussion of the emerging treaty faces a dilemma," Hart said at the opening ofhis own discussion of it.