The Americans for Democratic Action, which had been one of the earliest and most enthusiastic backers of Senator Eugene McCarthy's bid for the Democratic Presidential nomination, endorsed Vice-President Humphrey Saturday as the "best candidate" for the Presidency.

Meeting in Washington, the A.D.A. national board--headed by John Kenneth Galbraith, Paul M. Warburg Professor of Economics--endorsed Humphrey by a 71-16 vote, but urged him to make a "forthright call for an unconditional cessation of the bombing" of North Vietnam.

The New York Times, which yesterday endorsed Humphrey, reported that Galbraith had spoken in support of the ADA endorsement. Galbraith, who had seconded McCarthy's nomination at the Democratic convention in Chicago, was unavailable for comment.

"We urge Humphrey to build on his anti-bombing statement of last Monday night," the ADA statement said, "with a forthright call for an unconditional cessation of the bombing here and now."

"While he has moved substantially in our direction," the statement continued, "we are still far from satisfied with Hubert Humphrey's position on Vietnam."

The endorsement also called for Humphrey to break with the "reactionary elements of the Democratic Party." It said that the "best place to begin is with Mayor Daley."