Philadelphia — Walter F. Mondale and Edward M. Kennedy are clearly the early front-runners in the race for the 1984 Democratic presidential nomination. That was the verdict of the big conclave of Democratic leaders in Philadelphia.
Actually, Mr. Mondale and Mr. Kennedy were out front before they and other potential candidates showed their oratorical stuff over the weekend.
But their rhetorical successes in front of this critical and politically influential audience made it clear, to press and politicians, that they had indeed earned their No. 1 rating.
Philadelphia turned out to be a winnowing process. Except for Messrs. Kennedy and Mondale, the other hopefuls lost ground simply because they didn't show enough to make much of a favorable impression.
Sen. John Glenn's speech was thoughtful and fairly well received. But his quiet approach didn't stir the audience much. He had some good applause lines. But the applause was not rousing.
The judgment - not from all, of course, but from more people than a politician with an eye on the White House would want - was that he isn't forceful enough to be a winner.
Sen. Gary Hart of Colorado, too, delivered a persuasive speech but without arousing the audience. The appraisal from many of his viewers: He's bright, attractive, but perhaps not quite ready to make the run.
California's Sen. Alan Cranston also made something of a mark. But whispers were buzzing around the auditorium during his speech. The news that former Secretary of State Alexander M. Haig Jr. had resigned seemed to give Senator Cranston second billing. Again the assessment was that Mr. Cranston simply wasn't a strong enough figure to move into the presidential-bid circle.
Sen. Ernest F. Hollings of South Carolina gave a particularly good speech - one relatively short on what some viewers were calling tired rhetoric.
But again, Mr. Hollings didn't have the attention of his audience. Why? Simply because they didn't seem to be taking him seriously as a possible presidential candidate.
All in all, the assessment from a number of political observers was that this was an important testing ground for presidential candidates - in the sense that no candidate could gain much from his performance, but he could lose a lot if his party colleagues decided that he did not quite measure up.
So it was that Mr. Mondale and Mr. Kennedy kept their prominent position in the race by giving the crowd what they had expected: rousing speeches delivered with enthusiasm and political charm.
But the other hopefuls suffered, in a sense, from the exposure before the conference. They weren't graded as doing exceptionally well, especially in comparison to Mondale and Kennedy. Thus they receded, not out of sight, but enough to be of some concern to them and their advocates.
A longtime participant in presidential politics - Republican Sen. Bob Dole of Kansas - looked at the happenings in Philadelphia and commented: ''Mondale did well. Kennedy did well, too. The others were left in the dust.''
''It makes you feel good if you get a response from the audience,'' Mr. Dole told reporters over breakfast June 28. ''If you don't, you know you are going somewhere: back home.''
Doubtless the candidates on display in Philadelphia - aside from Mr. Mondale and Mr. Kennedy - read their response in different ways. Some may see their performances as satisfactory. They may view the experience as a beginning from which they can learn some lessons and build an effective candidacy.