The Sunni caliphate

The Buyids were a Twelver Shi'ite family who lorded over al-Iraq until Tughril Beg wrested it for the Seljuqs AD 1055. As contemporaries with the Fatimids across the Red Sea, and since their own (Arabic) imam was occulted, the Buyids saw fit not to impose themselves as Shi'ite caliphs as the Fatimiya did. But like the Fatimis (except Hakim), they tolerated the other religions. Among the tolerated subjects was that leftover 'Abbasi caliphate in Baghdad.

As the Buyids lost ground abroad - all Egypt fell to the Fatimids - the Iraqi caliphate grew more assertive at home. That caliphate chose the Four Schools' Sunnism with Hanbalism highest, and the exclusionary Zahiriya rejected. Enter the Akham al-Sultaniya. There are two but I deal with Mawardi's here. A short summary of Mawardi's political-theory can be had from Ringgren 1972 (pdf).

Mawardi promoted the "imam" over "temporal" suzerains... such as the Buyids. Melchert has Mawardi composing his Ahkam under al-Qadir's successor al-Qa'im, after AD 1045 and published before his death 1058. Al-Qa'im would outlast both men and the Buyids, and indeed Tughril (d. 1063), ruling - governing anyway - until 467/1074. Al-Qa'im lived to see Alp Arslan wallop the Empire at Manzikert (but let us not ourselves overextend, here!). Melchert suspects it was under al-Qa'im that Mawardi abandoned his oecumenism to become just another Sunnite NPC like Abu Ya'la.

Overall, as Twelvers, I would say the Buyids never had a chance. They ruled on behalf of an imamate who... no longer existed on this Earth. Mawardi could be read as Shi'ite-friendly theory, in case the Twelfth Imam returned; it was convenient for everyone that this pretense be kept up. But in the Iraq, the Sunnis had an imam already. They had Shaybani's imam: the 'Abbasi caliph, still un-deposed. Mawardi knew this and everyone reading him knew it, as al-Qadir and then al-Qa'im re-arrogated to themselves the temporal powers of al-Mu'tamid and then al-Muqtadir a century before. When the Seljuqs took over, their ideology allowed for 'Abbasi control in Baghdad. The Seljuqs rectified the names, as they say in China.