People rarely talk about leftist and Arab nationalist opposition groups in Saudi Arabia and the Persian Gulf. The focus now is fixated on Salafi extremism. Occasionally, there will be some discussion of liberal opposition and women’s movements (especially when women protest gender discrimination in Saudi Arabia by driving cars through Riyadh). However through the cold war, the left-right schism was the most important division in the Middle East. Rather than Sunnis versus Shi’a, the region was divided between conservative, religious monarchies and Arab-nationalist republics, which were secular somewhat slightly left-wing regimes inspired by Nasser and Ba’thist ideology. This left-right split was a key issue in the Persian Gulf where the Arab monarchies banded together with Shah of Iran to balance Ba’thist Iraq. The Saudis also fought a proxy war in Yemen in the 1960s against Nasser.
The left-right schism lost some of its importance during the 1980s. The Shah was overthrown, and the Islamic Republic of Iran scarred the Saudis so badly they backed Ba’thist Iraq during the Iran-Iraq war -even though they never really trusted Saddam Hussein. The end of the Cold-War and the Iraqi defeat in Kuwait finished the process. The left was “dead” and religious identity became the big issue. Interestingly, Arab spring has brought down virtually all of the Arab republics (Egypt, Syria etc… ) but left the conservative monarchies intact.
http://ma-alamal.com/2014/08/06/nationalist-and-leftist-movements-in-saudi-1/
http://ma-alamal.com/2014/08/10/nationalist-and-leftist-movements-in-saudi-arabia-2/
IR Theory & Practice 