The Khalifate...Da'esh claims it is restoring the Khlifate, as if it is doing one of the continuing--to this day!-- PhD theses at Oxford, or Princeton on the decline of the Ottoman Empire. Piiful result of decades of efforts by pro-Israeli professors to show that medieval Islam was anti-religious minorities, misinterpreting the position of "dhimmis" to be a stigma in the societies of medieval Islam as awful as the stigma towards Jews under national-socialism of Hitler.
From the PhD theses at Princeton, Oxford and Harvard under the perverted leadership of people like Bernard Lewis, studying the restoring the Khalifate and the position of the 'dhimmis"--oh, how I hate that word and the distorted a picture of an Islam (which gave FULL rights not only to its religious minorities, but also to the western trading communities which formed enclaves in the middle east during the Crusades) which it connotes!--the idea of the restoration of the Khalifate goes right into the US military, who gave a big boost to the idea as a way protect Exxon Mobil oil from the religious take-over of the great Mosque of Mecca in Saudi Arabia in--when?--1979, shortly after the Iranian revolution. Since 1979, the US funded the Bin Laden group to put pressure on the Soviets to leave Afghanistan, and later invaded Iraq at the request of, and with the financing of, Saudi Arabia, all the time re-inforcing a version of the Princeton-Oxford-Harvard PhD theses on the Khalifate.