Washington — The White House is concerned that President Carter may have to give up so much to Senator Kennedy in shaping the Democratic platform that the document's liberal tilt will give Republican Ronald Reagan the election.
"If Kennedy comes into the convention with 35 to 40 percent of the delegates -- and that seems quite possible -- we'll have to give him an awful lot on the platform. No doubt about that." So says a top Carter adviser.
"If we have to give Kennedy and the liberals too much," a key administration political source says, "we could turn over much of the mainstream of voters -- many moderates as well as conservatives -- to Reagan. But it looks like we're going to have a real fight to keep that from happening."
The President faces an additional and related problem. To ensure that Senator Kennedy supports him in the fall election, Mr. Carter must give him something.
That "something" appears to be in the shaping of the ideological thrust of the President's own quest for re-election.
Says another administration source: "That's really why Carter has come out of the Rose Garden. He's out to win most of these final primaries -- or, at least, to cut his losses.
"The better he looks in those primaries the more leverage he will have in shaping a Carter platform -- one that will be more likely to be attractive to the Majority of the voters."
Publicly, the Carter administration foresees no problem with the Kennedy forces at the convention.
Says Carter campaign chairman Robert Strauss:
"Senator Kennedy isn't saying give me this and I'll give you that. He wouldn't say it -- he has too much class. And we have too much class to give it to him."
Mr. Strauss, talking to reporters over lunch May 7, then added: "The President is not going to compromise his principles. . . . But platforms are usually hammered out in a spirit of compromise, and I don't think there will be that much difficulty. . . .
"When I look at Kennedy's voting record and how supportive he has been of President Carter's policies, I don't think it will be a great problem to work out a compromise."
What Mr. Strauss seemed to be saying was that there would be a platform compromise with Senator Kennedy but one which, somehow, would not compromise Mr. Carter's principles.
But Mr. Strauss also appeared to concede the President's convention problem. He responded to the question "Why is Kennedy staying in?" with this reply: "He wants to have influence on the convention and on the platform."
As for the senator, he is not willing to officially concede his goal is anything less than winning the nomination.
Yet key democrats close to the Mr. Kennedy say he has pretty much given up, but that his intentions now are these:
* Put a clear Kennedy-liberal imprint on the convention, particularly on the platform.
* Stick with the party -- and with President Carter -- in order to prevent a party split that might last until 1984.
Senator Kennedy's hopes now are based squarely on becoming the nominee four years hence, according to these sources. They say he does not want to hurt his prospects by antagonizing Democrats who support Mr. Carter, Democrats he will want to have behind him in 1984.