Washington — Already, long before the next presidential year, Sen. Edward M. Kennedy is regarded by many influential party professionals as the man to beat for the Democratic nomination.
From these savvy politicians comes this capsule assessment: If nothing changes, Kennedy has it - it's his to lose.
This assessment is reinforced by a new Gallup poll, released Sunday. The survey shows that among Democrats, Mr. Kennedy is a 2-to-1 favorite over former Vice-President Walter F. Mondale for the '84 presidential nomination.
But how could Kennedy lose it? By some new and damaging disclosures on Chappaquiddick, some observers say, or by some bad blunders, such as his lackluster TV interview with Roger Mudd and his comments about the Shah of Iran during his race for the nomination in 1980.
Knowledgeable observers provide several reasons for Kennedy's particularly strong position today:
* Labor is leaning heavily toward him. Further, the AFL-CIO has decided to endorse a candidate in its midwinter meeting just before the 1984 primaries.
''Think what that endorsement would do for Kennedy,'' says one highly placed Democrat, who personally would accept Walter Mondale as the nominee and perhaps prefer him over the Massachusetts senator. ''That endorsement of itself would make him almost unstoppable.''
* Black voters would appear to be almost totally behind Kennedy. Part of this is the ''Kennedy mystique'' - the feeling among most blacks that any one of the Kennedys is their friend. So there is intense, almost passionate support for Kennedy among these blacks. And that means they are likely to vote in large numbers, thus increasing their influence on the result beyond what would have come about in a normal turnout at the polls.
* The liberals are with Kennedy - or at least most of them. The senator, more than Mr. Mondale and other possible candidates, is widely viewed by liberals as the person who would most likely carry their banner forward as a president. Liberals say they tend to feel that Kennedy, like his brothers, sees social issues the way they do and that he is passionately committed to liberal goals.
* The highly influential Jewish community is actively giving more support today to Kennedy than to other possible candidates. The Monitor has learned that Kennedy's list of contributors is much larger than that of any other potential Democratic candidate - including Mondale, Sen. John Glenn (D) of Ohio, Sen. Alan Cranston (D) of Califoirnia, Sen. Gary Hart (D) of Colorado, and Sen. Ernest F. Hollings (D) of South Carolina. For years some of the most generous contributions to Democratic candidates has come from prominent wealthy American Jews.
Are Kennedy's personal problems behind him? The judgment of these professionals is that while Chappaquiddick will always be on Kennedy's back, the public memory of this has faded a bit, particularly among younger voters.
''It may defeat him in the general election,'' a veteran Democratic activist said, ''but unless something new is disclosed, it won't keep him from getting the nomination.''
Monitor conversations with Democratic leaders in all geographical regions evoked similar appraisals.
South Carolina's state Democratic chairman, William J. Bryan Dorn, who is committed to Senator Hollings, says: ''There would be those who would vote against him (Kennedy) for personal reasons. But this is wearing off.''
Political analyst Richard Scammon says that of those Americans who now oppose Kennedy, most do so because of his liberalism, not because of Chappaquiddick.
The South presents Kennedy with his biggest problem in gaining the nomination. But Democratic experts are becoming convinced that Kennedy won't have to concern himself much with resistance in the South in his bid for the nomination. They feel he will be able to pick up early momentum in the Iowa caucus and New Hampshire primary - and the nomination will soon be wrapped up.
Kennedy's adversaries clearly hope the Massachusetts senator will be eliminated, because, in their view, the national convention delegates will finally conclude that Kennedy's personal past will make him unelectable.
But the growing perception in the top circles of the Democratic Party is this:
The Kennedy boomlet is already becoming almost a Kennedy boom. Thus, he may well be able, through the primary route, to fill the convention hall with enough delegates to give him the nomination. Thus, too, the question of his electability may never be a central part of the decisionmaking process out of which the next Democratic presidential nominee is chosen.