WASHINGTON, June 8, 1988 (UPI) -- President Reagan placed some restraint on his post-summit exuberance Wednesday by injecting a note of caution into his declaration the superpowers ''may be entering a new era of U.S. and Soviet relations.''
Speaking to out-of-town reporters about his talks with Soviet General Secretary Mikhail Gorbachev, Reagan qualified his previous optimism ever so slightly in the face of doubts raised by others within his administration.
''Under Mr. Gorbachev, the Soviets have a leader who appears to want to change things and who may actually be able to change things,'' Reagan said. ''His promotion of perestroika and glasnost gives us hope, although we remember that old American political adage: 'Trust everybody, but cut the cards.'''
After ballyhooing the summit for days as symbolic of a turning point in U.S.-Soviet relations, the White House stated that signs of change under Gorbachev had not erased deep-seated disagreements and sources of conflict.
In remarks filled with admiration for the Soviet people, Reagan repeated his observation that reform-minded Gorbachev ''is different'' from previous Soviet leaders and echoed British Prime Minister Margaret Thatcher's view that ''he's someone you can do business with.''
At the same time, he said, ''That doesn't mean you lower your guard.''
''Today, we can say with caution that we may be entering a new era of U.S. and Soviet relations,'' he said. ''It's been a long time coming, but unlike past improvements that saw only a brief day, I think this one will have a broad and stable footing. If the Soviets want it to grow, it can and it will.''
White House spokesman Marlin Fitzwater said the encouragement Reagan reported in the aftermath of the summit ''doesn't mean he's any less concerned about the Soviet presence and their threat to the United States and their policies.''
His comments were intended to make the upbeat White House attitude conform with a warning sounded by Defense Secretary Frank Carlucci and a chord of doubt struck by Bush regarding assertions of change in the Kremlin.
Carlucci said Monday in Tokyo that the Soviet Union continues to pose ''a very substantial military threat'' that must not be obscured by the expressions of goodwill and personal rapport that emanated from the summit.
On Tuesday, Bush disagreed with the post-summit view taken by Reagan that ''profound change'' that could have a significant impact on superpower relations is taking place in the Soviet Union under Gorbachev.
''The president and the vice president are in total agreement with the idea that our basic relationship with the Soviet Union is one of caution and concern,'' Fitzwater said.
Shrugging off the apparent difference of opinion within his administration, Reagan told reporters Bush was only ''being as careful as we all must be.'' He said optimism about improved U.S.-Soviet relations must be tempered by his oft-repeated Russian proverb ''doveryai no proveryai -- trust, but verify.''
Reagan said he felt he had been ''dropped into a grand, historical moment'' during his visit to the Soviet Union, the first by an American president in 14 years. He described the Soviet citizens he saw and met as ''really wonderful'' and again singled out the Soviet women for praise as ''the biggest and most powerful stabilizing force in that society.''
''I couldn't believe it,'' he said. ''After all the years of propaganda that we're all villians on this side of the ocean and everything, the Soviet people were the warmest, friendliest, nicest people you could ever meet.''
On a more substantive level, Reagan insisted the summit had been a success even without blockbuster agreements and chided the news media for past coverage ''geared more to the hunt for headlines than to the realities of business.''
''In fact,'' he said, ''each of my four meetings with Mr. Gorbachev has produced significant steps forward.''
Having resisted summitry for the sake of summitry in his first term, demanding that such meetings be well planned and assured of success, Reagan signaled a change in his thinking by saying that for genuine improvement in superpower relations to occur, ''from time to time the leaders must step in and exercise leadership.''
''They must agree on a common set of broad goals so that those under them have a clear and common green light to move forward,'' he said. ''That's been the purpose and accomplishment of these four summits.''