THE ADJECTIVE that leaps to mind when Mikhail Gorbachev strides into a room is "clean-cut." The noun that usually accompanies it is, of course, "American." But the new star of the East has that same quality.

The other members of the entourage that followed him out from behind the shirred salmon-pink curtains of the auditorium of the new Soviet embassy-the building that some in Congress think should be crushed, burned or exploded like the missiles covered by the INF pact -- looked weary and puffy-faced, like men who have spent too much time in hotel rooms eating bad food.

Gorbachev, in his medium-dark blue Italian suit and his coordinated blue and rose tie, looked fresh, tanned, alert.

He took his seat at the center of the long table, which had l6 poinsettias neatly lined in front of it. He pushed away the translation gear, fished into his briefcase pulled out his eyeglass case, removed his glasses, put them on, arranged some large cards in front of himself and began in a mellow baritone, "Ladies and gentlemen and comrades."

The Soviet leader launched into a two-hour performance that seemed as much calculated to define himself as to brief the world on the results of his three-day dialogue with Ronald Reagan. He was calm and efficient, completely in charge. His face is expressive, his gestures more so. He said not a word that would ruffle his host, annoy Americans, offend anyone's intelligence or raise questions about his own sincerity. There were no slogans, no cheap shots.

"I would like to find some precise words so that I don't go to one or the other extreme," he said by way of opening. He didn't in almost 65 minutes of explanation, which for a Marxist is relatively succinct.

It was evident, despite his resolute emphasis on the positive, that he was going home with little more than what he had come with, namely two signatures on the INF treaty. In his address to the 70th party congress in October, he had said that the world would expect more.

But he resented a question suggesting he might be disappointed. Two of the new initiatives with which he had been peppering poor Reagan had been rejected: a disarmed corridor in Europe, an SDI test-ban for the duration of reduction talks.

"You are pulling me the wrong way," he said sternly, "I cannot add to my introductory remarks."

He was as determined to put a good spin on the summit as he was to avoid any particulars about his plans for withdrawing from Afghanistan. He is a master of detail and obviously could discuss the merits of any weapons system, but he was in his broad-strokes mode.

He was presenting himself as the leader the peace movement has been seeking for 40 years, ever since the bomb burst over Hiroshima. And he is too discplined and rational, too concerned with disarming U.S. doubts and fears, to risk being thought vindictive or even reproachful.

Of his initiative for a mutual moratorium on SDI testing, he said simply, "We did not meet with understanding on this important question." Then, mildly, "We are not losing hope that this very important invitation of ours to the American administration . . . will be given serious thought."

He suggested that the administration, this being a democracy, "might see fit to consult with the people." He knows what the polls say about peace.

His constituency, he seemed to be saying, is larger than Ronald Reagan's. It is a world that wants an end to the arms race.

His people are the intellectuals, the physicists, doctors, artists who have led the way.

He could not, however, completely conceal a certain emnity towards the free press that was understandable in a man from a country where reporters do not ask pesky questions. Gorbachev lost his cool only once during his stay, during a meeting with publishers when the human-rights issue was put to him. He said Americans should mind their own business.

In his press conference, the refusednik question inevitably came up again, and he spread his hands wide in frustration: "One and the same question . . . 2,000, 500 . . . ." He put their numbers at an unprecedented low, 252, and gave the standard alibi that they know too much.

"But you try," he said echoing every American politician since Thomas Jefferson, "to put us in to a corner. That is not what the media is for. People want to lead a better life. They want a better understanding of each other. They want to make friends."

He is a political leader to make Americans weep. None of the men who want to be president are in his intellectual league. Mario Cuomo is as smart and purposeful, but he isn't in the race and he doesn't know as much about nuclear arms. Gorbachev has made his mark in the campaign. But he's trying to revise the famous question, "Who can stand up to Khrushchev?" to, "Who can go into the room with Gorbachev and end the arms race?"

Mary McGrory is a Washington Post columnist.