Washington — The Carter campaign is sensing dangerous slippage in its political position because of growing public impatience with the President's handling of the hostage problem.
Now a survey by Patrick Caddell, the President's pollster, gives challenger Edward M. Kennedy a lead of 43-to-40 percent over Mr. Carter among Democrats in Pennsylvania, where the primary is set for April 22.
The political analysis being expressed at the highest level of the Carter campaign comes down to this:
* A genuine Kennedy comeback, where the Massachusetts senator somehow wrests the nominations away from Mr. Carter, is not envisioned.
Instead, Carter delegate-counters see the task ahead for Senator Kennedy, even if he should pick up steam in Pennsylvania, as well nigh impossible.
* What concerns the President's campaign team the most now is that the falloff of public support, because of the Iranian crisis, is likely to help keep the Kennedy challenge alive for weeks to come -- enough so as to make it impossible for the President to turn his guns, and strategy, in the direction of Ronald Reagan. Said one Carter political adviser:
"We could finish Kennedy off in Pennsylvania. And it looked like we might -- that Gallup poll of a week ago had us 10 points ahead. But now -- well, it looks like Kennedy will keep biting at us and hurting us, unless we can somehow get the voters behind us again on the crisis in Iran."
* What really concerns Carterites is that the continued strong challenge from Senator Kennedy may further divide the party and make it impossible for the President to bring the Kennedy faction behind him after the convention.
Mr. Carter is intensifying the pressure on Iran, setting a specific date by which he has told the principal allies of the United States that he expects them to have broken diplomatic relations with Iran if the hostages are not freed.
Mr. Carter also has announced that all Iranians will be forced to leave the US when their travel documents expire unless there are "compelling humanitarian reasons" for them to stay.
Says one key Democrat in the Carter camp:
"We know that the voters, or a lot of them anyway, aren't really turning to Kennedy. But they are beginning to send out a protest vote against Carter -- on the hostages, on inflation, on high interest rates, and more. And we simply must do something to turn this around."
Presidential assistant Tim Kraft, who runs the campaign under the overall direction of Robert Strauss, publicly is putting most of the blame for the Carter decline in Pennsylvania on the President's unwillingness to campaign there. He says Senator Kennedy's presence in that state -- "He's there all the time" -- is pulling the voters in his direction.
But the private thinking among Mr. Carter's top political hands puts the blame for the President's slippage squarely on the issue of voter dissatisfaction with his performance -- particularly his inability to free the hostages.