Washington — Rather than undercutting the President, the Kennedy campaign thus far is strengthening the Carter candidacy. This is the latest verdict of many Democratic leaders in Congress and around the United States.
Furthermore, Carter supporters are saying that Sen. Edward M. Kennedy has galvanized Mr. Carter into action, thereby making the President a stronger candidate, both early on and in the long run.
The President and those close to him also attribute the commanding lead Mr. Carter holds over the Massachusetts Senator in the polls (Louis Harris now shows a 58 to 38 Carter advantage among Democrats) to "events."
They cite the rallying of the US public behind Mr. Carter in the Iranian crisis along with Mr. Kennedy's less-than-impressive early campaign performance.
Carter supporters think that Mr. Kennedy has acted mainly as a prod -- pushing the President into his best political form and causing his campaign organization to come up to optimum level well before the presidential primaries.
In the early weeks of the Kennedy challenge those in the Carter camp were complaining that the Senator was undercutting the President's effectiveness -- both as a president and as a campaigner.
But that has changed. Mr. Carter has risen dramatically in polls rating his handling of the presidency. They show he has come up from far behind Senator Kennedy among Democrats.
Democratic leaders also are revising their judgment of the Kennedy challenge. Their assessment comes down to this:
* The Kennedy candidacy hasn't bruised the President as many Democrats had anticipated. Instead it has been a stimulus -- making him a better candidate. This could help Mr. Carter in both his upcoming primary battles and in mounting a strong campaign next fall if he gains the nomination.
* There is no evidence that the challenges from either Senator Kennedy or California Gov. Edmund G. Brown Jr. have undercut Mr. Carter in fulfilling of his presidential responsibilities.
If anything, the Kennedy criticism of the Shah only served to increase public support for Mr. Carter's handling of the crisis in Iran.
Now the President's decision not to debate in Iowa appears to be winning public support -- even though both Senator Kennedy and Governor Brown are criticizing Mr. Carter for dropping out.
* The Kennedy challenge itself has sputtered so much that it appears likely that the Senator may be having private second thoughts about running.
In fact, Kennedy people in some areas are beginning to talk along this line: that the Senator now must carefully avoid letting his criticism of Mr. Carter become too sharp-edged and bitter lest he stir up a strong anti- Kennedy feeling among Carter Democrats. That result could shut him out from running for President again -- should he fail in his bid this time.