If the proverbial man from Mars had been in Washington during the early weeks of the Reagan administration, gone home, and just returned this past week, he would be hard pressed to understand the change.
Can you remember those early weeks when the President was talking like John Wayne buckling on his gun belt, when his secretary of state was going to ''draw the line'' in Central America, when the new administration was going to root out communism ''at its source''?
The general idea was stern and firm action against the forces of evil that lie and cheat -- and steal -- unless strong men make themselves stronger first. There was no room for talking to the men of Moscow in the rhetoric of those early Reagan days.
Where are we now?
President Reagan has suggested that he would like to meet Moscow's Leonid Brezhnev informally and tossed out June at the United Nations in New York as a possible time and place. Mr. Brezhnev has come back with the idea of a proper ''summit'' conference in October either in Finland or Switzerland.
It seems doubtful that either meeting will take place. Assuming Mr. Brezhnev is well enough in June for a trip to New York, would he want to go there at the risk of running into angry street demonstrations by Poles, Afghans, and others people who disapprove of his country's policies?
And could Mr. Reagan put together an American position by October for a useful formal ''summit'' with the Soviets? Could the Soviet leaders get ready in time for such a summit when their thoughts and energies are probably concentrated on the question of the Brezhnev succession?
But in these changed times, the leaders in both Moscow and Washington vie with each other in peaceful thoughts and words. Mr. Reagan echoes Mr. Brezhnev in asserting that nuclear war is ''unwinnable and unthinkable.''
A massive public desire for reassurance about the future of the human race has taken over the political scene in Washington. Perhaps Mr. Reagan remembers when Richard Nixon's White House was barricaded against a sea of antiwar protesters. He certainly does not want any repetition of such scenes. He is echoing the wishes of the antinuclear demonstrators for an arms reduction or a freeze.
The antinuclear movement has caught on and made a dent on Washington appearances and attitudes. This past week it surfaced as Ground Zero Week. It is one of the political forces that have turned Mr. Reagan's priorities around.
The President came to the White House putting the making of more guns first. Negotiations with the Soviets were to come later, after the new weapons were in hand. But it will take years to get the new weapons in hand. The priority concern now is something that at least looks like a search for new arms controls and limitations.
The John Wayne costume has been put into the White House attic, certainly for the time being. It might have been used in the Falkland Islands affair. John Wayne upheld the law against the ruffians who steal other people's property.
As of this writing Mr. Reagan is still trying to talk the Argentines back out of the islands they took by force. John Wayne would not have been so tender of the feelings of the Argentine leaders.
The transformation from hawk to dove also applies in Central America. Washington is exchanging proposals for a new and peaceful relationship between the US and Nicaragua. There is even talk behind the potted palms about possible ways and means of smoothing and easing relations between the US and Cuba.
There is a question whether the change of costume will come in time to be of help to West German Chancellor Helmut Schmidt. Mr. Reagan is scheduled to go to West Germany in June. The antinuclear movement is powerful there, particularly among the younger generation.
Mr. Reagan has become identified in the minds of many Germans, and other Europeans as well, with recklessness about such weapons. Will his visit add fuel to the antinuclear movement and to anti-Americanism?
The defense of West Germany itself is based on the use of nuclear weapons as a deterrent. The idea of deploying a new generation of US nuclear weapons in Germany to counter Soviet SS-20s was not initiated in Washington. It came originally from Chancellor Schmidt himself.
How can Mr. Reagan remain loyal to Mr. Schmidt's design for defending West Germany and at the same time try to defuse the antinuclear movement that threatens to unseat the German chancellor?
The only possible answer would lie in successful arms control negotiations with the Soviets. That would get Mr. Schmidt off the hook. But there is little chance of Moscow and Washington getting together in the near future on an agreement that would, in fact, reduce the number of nuclear weapons in the arsenals of the two great superpowers and put new restraints on their prospective use.
Despite all the anxieties of the times, there was one relatively bright spot in recent days for Washington: The Chinese apparently managed to accept the modest resupply of US arms to Taiwan without doing anything drastic.
Peking had at one time threatened to break up relations at the ambassadorial level if Washington went ahead even with spare parts for Taiwan. There has been no break in relations. That danger seems to have been surmounted.