Arthur M. Schlesinger Jr. '38, American historian and advisor to Sen. Robert F. Kennedy '48, last night advised liberals not to oppose President Johnson's renomination in 1968.

Schlesinger told an audience of 100 in Lowell Lecture Hall that an open split in the Democratic Party would encourage the Republicans to nominate the man they really want but who they feel cannot win against a united Democratic party - Richard M. Nixon.

If the Democrats are unifled, Schlesinger believes, there is hope that either the Republicans will "rise to the occasion and nominate a reasonable candidate" or liberal Democrats will exert enough pressure so that a Democratic administration can slow down the war.

The historian called the administration's escalation of the Vietnam war a part of a foreign policy which "would rejoice the heart of John Foster Dulles." He urged the Democratic party to reorganize around a coalition of university intellectuals, liberal clergy, and people concerned with the Negro revolution and urban movements.

Such a coalition can succeed, he said, while a third party based on opposition to the Vietnam war would "probably pull less than a million votes" and only aid conservatives.