 In 1967 he persuaded Czechoslovakia, Poland, Hungary, and Bulgaria to conclude bilateral mutual assistance treaties with East Germany.The Ulbricht Doctrine, subsequently signed by these states, committed them to reject the normalization of relations with West Germany unless Bonn formally recognized East German sovereignty.Ulbricht also encouraged the abrogation of Soviet bloc relations with the industrialized West, and in 1968 he launched a spirited campaign to convince the Comecon states to intensify their economic development "by their own means."