After seven months of long-distance combat, President Carter and Sen. Edward M. Kennedy (D-Mass,) will meet face to face at the White House today and find out how much room there is for conciliation between them.

The meeting of the two Democratic Party antagonists, whose long primary-election battle grew increasingly personal in its later stages, wasd arranged during a five-minute telephone conversation between the two men yesterday that White House press secretary Jody Powell charcterized as "very cordial."

White House and Carter campaign operatives are now moving actively to secure Kennedy's withdrawal from the presidential race, in hope that this will prevent a bitter, party-splitting clash at the Democratic National Convention in New York in August.

But Kennedy, in remarks Tuesday night after he won five of the last eight primaries, and some of his staff aides, in interviews yesterday, were talking defiantly about battling the president right up to the convention.

Weighing against this, however, were the views of some important members of the party's liberal wing -- whose support Kennedy must have to continue -- indicating that they think the contest is effectively over.

But, at a reception last night at a northwest Washington home, Carter said he expects Kennedy to continue his challenge all the way to the convention.

"My anticipation is that he will carry his forces, his popularity, his strength, his delegates and his deep belief in the issues to the convention," Carter said.

Speaking to about 45 congressional supporters, the president said that to the extent he and Kennedy "can agree on common ground, then the harmony will be quite early. To the extent we don't agree at the platform committee, we'll let the delegates make a choice. I look forward to that contest, if necessary."

Asked earlier yesterday whether Kenney sounded "like he was being conciliatory" during their telephone conversation, Carter said, "I wouldn't say that, no."

But the president also predicted that the meeting today would be "very cordial, not strained," and in a gesture to Kennedy's liberal supporters, promised that the party platform would be written in an "open democratic process" in which their views would be heard.

When Carter first suggested Saturday that he and Kennedy should get together after Tuesday's primaries, Kennedy's initial reaction was uncompromising.

"I welcome the opportunity to meet with the president at any time," Kennedy said then. "I would say to him that prior to the time the ballot is called at the convention, we ought to havce a debate on the crucial issues . . ."

Kennedy also seemed to reject last weekend any suggestion that he and Carter might work a compromise on the party platform. "The Democrats ought to make that decision," he said. "It shouldn't be just a matter of sitting down between the president and myself."

Kennedy's immediate campaign staff, buoyed by the senator's relatively strong showing Tuesday, seemed to echo this hawkish attitude yesterday.But among Kennedy supporters in interest groups and in Congress -- the people the candidate would presumably contact before choosing his course -- the mood seemed more cautious.

Rep. Morris K. Udall, who faced a similar decision when he lost to Carter in the primaries four years ago, indicated that it is time for Kennedy to throw his support behind the nominee. "Carter has 300 more delegates than he needs," the Arizonan said, "and it's unrealistic to talk about invading that convention and turning 400 delegates around. It's not going to happen, and trying it would offend a hell of a lot of people."

Udall said that he had told Carter supporters this about Kennedy: "Don't crowd him. The rhetoric got pretty harsh, and he got into a pretty tight corner with a call for debate. It's hard for a guy who is saying harsh things on Monday to stand up and endorse the fellow on Wednesday . . . I think he'll come around, but he's pretty well dug in."

Referring to former senator Eugene McCarthy of Minnesota, who became increasingly isolated in his party after losing the 1968 nomination fight and who ran for president in 1976 as an independent, Udall said he thought it important that Kennedy not be seen as "another McCarthy."

He recalled that he met with Carter about two weeks after the Ohio primary in 1976 and told the eventual nominee that he would support him, but that "my people would feel a lot better if my name was put in nomination and they had a chance to give me a cheer before they go to work for you."

Udall said that Carter had accepted that procedure in 1976 and implied that he hoped the president would be equally understanding of Kennedy and his supporters in 1980.

Rep. Paul Simon, a key Kennedy backer in Illinois, said, "I have not talked to Kennedy. My instinct is that the ballgame is for all practical purposes over, but as long as Kennedy is a candidate I'm going to continue to be for Kennedy. But at this point, I don't think there is anything to be gained by his continuing as a candidate."

Simon said he did not think it was worthwhile to remain a candidate just to "make a fight over the party platform."

He said only Kennedy could judge whether continuing to run would damage his standing in the party or his future presidential prospects, "but not healing the breach at this point does cause some problems for other people. It probably reduces the Carter margin in the fall, and it may hurt guys like [iowa Sen.] John Culver who have to run with Carter."

Jery Wurf, president of AFSCME, the public employes' union which has endorsed Kennedy, said he would support a continuation of the Kennedy candidacy "to sensitize the party to the question of accountability on the issues," but would not "go along with just a protest vote. I would live very comfortably with the 1976 platform," Wurf said, "but the problem is that president pay little or no attention to the platform.We need a commitment that is more credible than the usual campaign rhetoric."

Kennedy himself seemed to concede, in an interview three weeks ago, that the platform might not be worth a major convention fight. "Sure, I think we can get a lot into the platform," he said. "The question is, does it mean anything?"

Among those Kennedy workers who still think their candidate can win the nomination -- there are several -- it is felt that a forceful, successful fight at the convention over platform planks on inflation and budget-cutting might spark a general delegate mutiny that would turn the tide from Carter to Kennedy.

But that would require turning an almost overwhelming tide. According to a delegate count by United Press International -- a count that includes delegates locked up in primaries and projections of delegates from some states where the selection process is incomplete -- Carter now has 1,962 delegates -- 296 more than he needs for nomination and 751 more than Kennedy has.

A total of 19.1 million democrats voted in the three dozen primaries this year. Carter won 9,975,801 popular votes -- 51 percent of the total Kennedy ended up with 7,330,295, or 38 percent. Other candidates and uncommitted" received 2,165,662 votes, or 11 percent.

According to Powell, Carter called Kennedy at 6:30 p.m. Tuesday, before the polls in the eight final primary states had closed, but was told that "the senator was resting and could not be disturbed." He said the president placed another call at 10:30 p.m. Tuesday and was told Kennedy was on his way to his campaign headquarters and could not be reached.

Yesterday morning, Powell said the purpose of the Carter calls was to congratulate Kennedy "on running a good race." The White House spokesman steadfastly refused to be baited into criticizing Kennedy for not returning the calls sooner, and the president later said the senator's call to him at 2:30 p.m. yesterday came "in a adequate, time fashion."

Carter called reporters to the Oval Office late yesterday to issue a statement on congressional attempts to overturn his oil import fee. In the process he discussed the Kennedy phone conversation.

He said Kennedy told him "that he thought it would be important for use to get together at an early time to discuss the political situation."

This suggested that Kennedy took the initiative in setting up the meeting, but it was not clear.

The president said that at today's meeting he intends to "congratulate him on having run a good campaign, and see what we can do together to work together in the future to meet the Republican challenge successfully."

Carter also brushed aside criticism by some Kennedy allies that his failure to win primaries in such major states as New York, New Jersey and California indicated his weakness as a general election candidate.

"You can't win them all," he said. "I have won about three-fourths of the contests. I wish I could have won 100 percent, but I didn't because I had some formidable opponents and because we had some very difficult decisions to make. I think we did much better than we thought we would seven or eight months ago."