I apologize if this seems an esoteric topic, but it is one that seems to be a matter of seriously contentious dispute, as well as one that Iis relevant to various controversies and issues in the Middle East now. It is triggered by the biggest argument I have ever had with Juan Cole, whom I usually agree with, and indeed I agree with the vast majority of his recent posthttp://juancole.com/2017/09/saudi-arabia-improve.html that advises Saudi Arabia on how they can make themselves look better to the rest of the world, which includes such obvious items as allowing women to drive (the last of 7).
My disagreement with him was over a line just dropped incidentally that he would later defend ardently, that the official Saudi theology/ideology of "Wahhabism" is "not Sunni." I challenged this, pointing out that 1) the Kingdom of Saudi Arabia (KSA) officially uses as its official Shari'a law code the Hanbali code, one of the four Sunni Shari'a codes, and 2) that KSA is currently claiming to lead a global Sunni movement against the global Shia movement, even if this may well boil down simply to a local power struggle between KSA and Iran. I think Juan agrees with those two points, and also that Wahhabism and Salafism are not identical, in contrast to claims by many ignorant commentators.
I now accept that Juan is right about certain matters I differed with him about. The founder of Wahhabism, Muhammed ibn Abdel-Wahhab, who formed an alliance in 1744 with the founder of the Saudi dynasty, Muhammed ibn Sa'ud, did not make as his primal demand that the very strict Hanbali code be adopted by the Saudi family as part of their alliance. He had his own idiosyncratic theology that mostly attacked local practices such as worship of saints and their shrines. And he denounced the existing Sunnis and all other Muslims who did not follow his version of Islam to the point that they could be killed, although it seems that his worst wrath was against Shia and Sufis. But his stance led and justified the view by many that his followers were not proper Sunnis, even though later they would adopt the proper, if extreme, Hanbali Shari'a code, although that would be following ibn Hanbal's follower, ibn Tamiyyah more specifically when they did so by a century or so ago. It was also the case that from the beginning Abdel-Wahhab's views were close to those of advocates of the Hanbali code, who included members of his family, including his influential grandfather.
Before we proceed to the relationship with Salafism, I recognize that part of the problem here more broadly is that the Saudis do not like being called "Wahhabi." It was a term first applied by their enemies in the past, the Ottomans, and taken up from them by the British, who established it in the general literature and discussion. Although most Wahhabis dislike the term, reportedly especially the new king of KSA, Salman bin Abdulaziz bin Abdul Rahman al Sa'ud, it has been also reportedly accepted by some scholars within that tradition. Nevertheless it must be recognized that what these Saudi Wahhabis prefer to be called is "Muwahuddin," which is usually translated into English as "Unitarian." Big surprise, nobody besides themselves or people super kissing their behinds calls them that. OTOH, they are not averse to being labeled "Salafi," which gets us to the core of this.
Before proceeding further I must note that all of this is highly controversial with many scholars, not to mention theologians and ideological propagandists spouting many lines on all this. But as near as I can tell Salafism ("Salaf" referring to the early period of Islam, during its first three or four caliphs) originated in Egypt in the mid-19th century at the world's second oldest university, al-Azhar in Cairo, with such figures as Jamal al-din al-Afghani and Muhammed Abduh. Following what my wife, Marina, and I have labeled a "new traditionalist" approach, they tried to reconcile both a return to the roots of Islam, the "Salaf," with modernism and science given the fall of Egypt under British control. In the early 20th century their followers would become more attuned to a more traditionalist view against such currents as socialism, with the founding of the Muslim Brotherhood (Ikhwan) in the 1920s by al Banna with more radical support form al Qutb.
In the 1950s and 60s Nasser would suppress their followers, and in 1962 King Faisal in Saudi Arabia invited many of them into KSA as he founded the Muslim League. Many moved there, becoming high school and university teachers. This would lead to a partial convergence of the traditions, with some calling what King Faisal advocated "pan-Islamic Salafism." This would be spread globally by Faisal as he funded madrassas around the world, many of them staffed by Egyptian Salafis. Eventually some of the Egyptian Salafis would split from the Muslim Brotherhood there to pursue a violent quest for their views, the Qutbist strand, with some of these becoming prominent in al Qaeda, such as its current leader, al Zuwahiri, formerly second in command after Osama bin Laden.
Wahhabism has its own historical origin prior to that of Salafism, nevertheless many now argue that either they are identical or that Wahhabism is a sup-part of Salafism, a possibly defensible position. Again, the Saudis themselves reject being called Wahhabi, prefer to be called Muwahuddi, and accept being called Salafi. Some claim they are not Sunnis, but even if ab-del-Wahhab did not initially accept the Hanbali code, they do now, and it is Sunni. I can understand that many Sunnis may not wish to be associated with them, but then many Christians do not wish to be associated with the KKK or the Inquisition. Tough.
I could go on as there is a lot more to this, but I think this will do for now. Good night.
Addendum: Oh yes. The violent extremist Sunni groups Daesh/ISIL and al Qaeda all claim to be Salafi, and some observers also claim that they are Wahhabi as well, although that remains not universally accepted. Hopefully I have helped clarify somewhat why that is the case.