PRESIDENT Reagan is beguiled over the idea of a summit meeting with Konstantin Chernenko. An exchange between a reporter and Mr. Reagan reflects this growing desire to sit down with the new Soviet leader:
Q. Mr. President, one of the purposes of a summit meeting with the Soviet Union has traditionally been education. If they come here, they'll find out what the prosperity is like. They are a closed group of leaders without much experience of the outside world. An American president can find out what their fears are. Would you regard such a summit meeting as useful and substantive simply for that educational purpose?
Mr. Reagan: I am tempted by what you say about educating them. I've never been in Marine One, flying at a low altitude over our cities and looking down at the homes that our working people live in, and all, without fantasizing what it would be like to have Soviet leaders sitting there and be able to point down and say: ''That's where the workers in America live. They live like that. How long are you going to cling to that system of yours that can't provide anything like that for these people?''
The President said an agenda was needed before he would agree to a summit. But his eagerness was evident when he talked of how much would have to be agreed on in advance: ''I think there has to be something.''
''Something?'' Would this have to be an arms-reductions pact? A source close to the President has said that Mr. Reagan would be willing to accept an agreed-upon agenda on less controversial topics, perhaps on economic issues, as the prerequisite for a summit.
Did Mr. Reagan have reason to believe that the new Soviet leader might be easier to negotiate with, might take a softer position in dealing with the United States? No, but he said he was sending out feelers to the Soviets.
Then he said that, with a new leadership in Moscow, there ''is someone there who has not gone out on record as making statements that he would then have to retract in order to change a position or moderate his position.''
Here Reagan added: ''We're going to try and take advantage of this to establish contact, communication, on the issues that divide us and see if we can't indicate or prove to them that they could be better off if they joined the family of nations.''
The President does not want to raise unjustified public expectations. He cited ''another President'' whose personal ''sizing up'' meeting with a Soviet leader had raised such expectations and how that get-together had quickly turned sour. He was probably referring to Lyndon Johnson's summit with Alexei Kosygin.
But Mr. Reagan seems more than willing to get together with Chernenko under circumstances where the only declared objectives would be rather limited - but where, without promising anything, he could seek to ease world tensions and, perhaps, make progress in private discussions on arms control or limitations.
We don't know all that was said in the meeting between Vice-President George Bush and the new Soviet leader, but it appears that Chernenko, too, is receptive to a summit. We could argue that the Soviet leader would first have to solidify his internal position before embarking on such an adventure. But it is also arguable that he could enhance his position of power by going to the mountaintop with Mr. Reagan, with the world watching.