I would like to digress from the current argument and throw my two Riyals in on the subject of Muhammad ibn abd Al-Wahhab and Wahhabism.
I must refer to the work of Netana DeLong-Bas, Wahhabi Islam: From reform and revival to Global Jihad The author makes an interesting case through a thorough scientific examination of Muhammad ibn abd Al-Wahhab's own writings to figure out if ibn abd Al-Wahhab was as radical as he is said to be.
Some interesting things were found. The influence of the radical 13th century Hanbali jurist Taqi al-din ibn Taymiyya in ibn abd al Wahhab's worldview is negligible. They were both Hanbali jurists with an emphasis on Tawhid, but the similarities end there. ibn Taymiyya's radicalism was born out of the Mongol conquest of the Umayyad Caliphate, so ibn Taymiyya was prone to reactionary calls of apostasy, for which the penalty is death. Ibn Taymiyya had no qualms about calling for violence, and stressed the need for an individual, offensive Jihad that would be picked up by Sayyid Qutb 680 years later. Wahhabism emerged in the Nejd in the 1750s, an area that had never been under foreign control. ibn abd al-Wahhab's own ism was not a reaction to foreign encroachment.
ibn abd Al-Wahhab displays an aversion to violence in his own writings, dismissing the notion of offensive jihad, and stating that Jihad is only a military action of a defensive nature. ibn abd al-Wahhab issued several restrictions on the "Sword verse" (9:5) because he felt it was too broad and believed that Islam would be better off proselytizing through charm than violence. For him, unbelief was an opportunity rather than a menace.
The Kitab Al-Tawhid, or the book of monotheism, ibn and al-Wahhab's most important work, does not mention the sword verse once. Of 341 citations, ibn Taymiyya is mentioned three times. ibn abd Al-Wahhab disagrees in these instances. This is critical. Tawhid (oneness) and shirk (association) are intimately linked. ibn abd al-Wahhab was staunchly anti-shirk, as was ibn Taymiyya, but there is another important difference here. If someone is guilty of shirk, that person is open to a call of takfir. Ibn abd Al-Wahhab presumed all persons innocent of takfir unless they were properly instructed in the faith. Much of Muhammad ibn abd Al-Wahab's writing is concerned with the preservation of human life and dignity, and ibn abd Al-Wahhab took a special concern to protect the rights and dignity of women. He ruled that men were responsible for their own sexual activities. A man could not blame his lust on a beautiful woman. Ibn abd al-Wahhab argued (paraphrase) "God made her beautiful, it is not her fault for being beautiful". Also, if there was a wedding, the bride and groom were obligated to get down and party so they could share their joy with the community.
Sounds like a decent cat. Where did it go wrong? Well, there's the link with Muhammad ibn Saud, the old arabian alliance between a warlord and an imam to have legitimacy for both sides of the axis. ibn Saud wanted territory. The conquest of Riyadh took two decades, finishing in 1773. It was in this year that a frustrated Muhammad ibn abd al-Wahhab retreated from public life, upset at the insincerity of his followers and the lust for power of the Saud clan.
In order to legitimize overthrow of a non-muslim (or not muslim enough) leader, the subsequent Wahhabis couldn't rely on ibn abd al-Wahhab alone. They had to look to ibn Taymiyya. Ibn Taymiyya spent many stretches in jail for calling for the overthrow of "takfir" leaders. To legitimize war against other Arabian rulers, there needed to be a precedent for Takfir. So, for a lust for power and territory, ibn abd Al-Wahhab's reformist, moderate message was warped by later followers to facilitate violence, which ibn abd Al-Wahhab himself couldn't stand. Throw ibn Taymiyya into anything, and there is a precedent in jurisprudence for violence and radicalism.