Babrak Karmal befriended fellow inmate Mir Akbar Khyber, who introduced Karmal to Marxism. Karmal changed his name from Sultan Hussein to Babrak Karmal, which means "Comrade of the Workers'" in Pashtun, to disassociate himself from his bourgeois background. When he was released from prison, he continued his activities in the student union, and began to promote Marxism. Karmal spent the rest of the 1950s and the early 1960s becoming involved with Marxist organizations, of which there were at least four in Afghanistan at the time; two of the four were established by Karmal. When the 1964 Afghan Provisional Constitution, which legalised the
Babrak Karmal room, the Afghan defence minister and the state security minister visited Karmal's office, telling him that he had to resign from one of his posts. Understanding that his Soviet support had been eliminated, Karmal resigned from the office of the General Secretary at the 18th PDPA Central Committee plenum. He was succeeded in his post by Najibullah. Karmal still had support within the party, and used his base to curb Najibullah's powers. He began spreading rumors that he would be reappointed General Secretary. Najibullah's power base was in the KHAD, the Afghan equivalent to the KGB, and not the party.