Democratic National Chairman John C. White yesterday warned that the movement to draft Sen. Edward M. Kennedy (D-Mass.) for the 1980 nomination might lead to an independent presidential candidacy that could cost Democrats the White House.

White raised the theory that former senator Eugene McCarthy's independent candidacy had a major impact on the 1976 election.

If McCarthy, whose candidacy has generally been regarded as inconsequential, hadn't run, Jimmy Carter would have beaten former president Gerald R. Ford by a landslide, white told a breakfast meeting of reporters.

To buttress his case, White pulled from his suitcoat pocket a two-page memo listing 1976 election results. Without McCarthy, a Minnesota Democrat, in the race, Carter would have carried California, Iowa, Maine and Oregon, all states he lost to Ford, White said.

In Iowa, for instance, if the 2.1 percent of the voters who cast ballots for McCarthy had voted for Carter he would have carried the state by one percentage point. If McCarthy voters had done the same in Oregon, Carter would have won by more than four percentage points, White said.

If the draft-Kennedy movement "escalates into a highly divisive situation, it would lead to the same kind of situation we had in 1976," White said.

The White House "is our most valuable asset as a party," he said. "I don't think we should throw it away."

White said Kennedy wouldn't approve of a third-party or independent candidacy. But, he added, "some folks are taking advantage" of Kennedy's popularity to bulid opposition to Carter.

White's statements represented his third major public attack in less than two weeks on draft-Kennedy efforts now under way in at least nine states. In the latest of those efforts, 150 liberal Democratic legislators and union officials launched a draft-Kennedy drive in Chicago Monday night.

After a closed-door meeting with White in the senator's office, Kennedy told the Los Angeles Times that he knows of no liberal alternative to Carter for the 1980 presidential nomination. He added that he intends to support the president against Gov. Edmund G. (Jerry) Brown Jr. of California or any other democrat who might challenge Carter.

Kennedy said he and White had been "maintaining open lines of communication and he indicated, of course, his strong support for the president, which I both understand and respect."

White said he told Kennedy that "the president is entitled to my support, just as John Bailey [then Democratic Party chairman] supported your brother John [in 1960]."

The senator laughed, White continued, and said, "I would expect you to support him [Carter]. That's your job."

On another subject, White said Rep. Morris K. Udall's (D-Ariz.) refusal to endorse Carter's reelection was due to fears about his own reelection in his home state. "If I were Udall, I wouldn't be endorsing the president right now either," White said.

Carter reportedly asked Udall, a leading liberal spokesman and 1976 presidential candidate, for his endorsement last week.