thereafter turkey once again put forward the idea of partition. the intensified fighting especially around areas under the control of turkish cypriot militias, as well as the failure of the constitution were used as justification for a possible turkish invasion. turkey was on the brink of invading when us president johnson stated, in his famous letter of 5 june 1964, that the us was against a possible invasion and stated that he would not come to the aid of turkey if an invasion of cyprus led to conflict with the soviet union. one month later, within the framework of a plan prepared by the us secretary of state, dean rusk, negotiations with greece and turkey began.