John Kenneth Galbraith, professor of Economics, and a Stevenson speech-writer, yesterday attacked the assumptions upon which the draft is based and suggested new ways of providing an armed force.

In a letter to the Sunday New York Times, Galbraith termed obsolete the concept that "military manpower must be produced cheaply." Since the United States can now afford the amount necessary to pay a volunteer force, the draft survives, in Galbraith's opinion, "principally as a device by which we use compulsion to get young men to serve at less than the market rate of pay."

Also obsolete, he contended, is the original assumption that the dangers of military service should be distributed equally. The present peacetime military service is no more dangerous than "ordinary civilian existence," he wrote, and a person living in a city such as New York during a war might be in as much danger as one serving in the army.

Galbraith cited the "highly regressive arrangement" of the present draft, charging that the system shifts the burden of military service from the "well-to-do taxpayer, who benefits from lower taxes, to the impecunious young draftee." This arrangement would not be tolerated in any other area, he felt.

An additional advantage to the implementing of fully-paid service would be the better-trained force that would result. This would eliminate the filling of the armed forces with partially-trained men, he added.