The Three Ruling Systems

The Hadith on the Advent of the Second Caliphate
God’s Messenger (God bless him and grant him peace) said: “The Prophetic Mission shall last amongst you so long as God wills. Then God shall suspend it if He so wills. Then shall come a Caliphal Government according to the Method of the Prophets. It shall last so long as God wills. Then it shall be suspended. Then shall come the reign of Mordacious Monarchy (that is, hereditary and oppressive monarchy). It shall last amongst you so long as God wills. Then it shall be suspended. Then you shall be governed by dictatorial regimes (the current dictatorships?), which shall last so long as God wills. Then shall come the reign of the Caliphal Government according to the Method of the Prophets.”
Source: The Hadith is reported by Imam Ahmad on the authority of an-Nu’mān ibn Bashīr (God be pleased with him).

Mordacious Rule
By Mordacious Rule [al-Mulk al-‘Ād] is meant that system of government based on hereditary power. The despotic ruler dies and hands over power to his son or relative.
Such rule characterized the Umayyad, the Abbasid, and the subsequent dynasties that had ruled the umma (the then-united Muslim community) against its will until the Ottoman rule. Those rulers were despotic yet generally never expressed antagonistic sentiments against Islam.

Tyrannical Rule
Tyrannical Rule [al-Mulk al-Jabri] represents the system of government of the protégés of colonialism, that is, the secular dictatorial regimes [absolute monarchies or false republics] that now govern throughout the Islamic world. Unlike their ancestors, they wage war against Islam in the name of the foreign enemies, and contribute to further dismembering and weakening the Muslim community through checking any revivalist endeavors undertaken by the independentist forces of Islam.