Article: To varying degrees, Nasser's statist system of government was continued in Egypt and emulated by virtually all Arab republics, namely Algeria, Syria, Iraq, Tunisia, Yemen, Sudan, and Libya. Ahmed Ben Bella, Algeria's first president, was a staunch Nasserist. Abdullah al-Sallal drove out the king of North Yemen in the name of Nasser's pan-Arabism. Other coups influenced by Nasser included those that occurred in Iraq in July 1958 and Syria in 1963. Muammar Gaddafi, who overthrew the Libyan monarchy in 1969, considered Nasser his hero and sought to succeed him as "leader of the Arabs". Also in 1969, Colonel Gaafar Nimeiry, a supporter of Nasser, took power in Sudan. The Arab Nationalist Movement (ANM) helped spread Nasser's pan-Arabist ideas throughout the Arab world, particularly among the Palestinians, Syrians, and Lebanese, and in South Yemen, the Persian Gulf, and Iraq. While many regional heads of state tried to emulate Nasser, Podeh opined that the "parochialism" of successive Arab leaders "transformed imitation [of Nasser] into parody".

Now answer this question: What Nasserist usurped the King of Yemen?
Abdullah al-Sallal