For edicts to carry divine imprimatur, they must be unambiguously stated in the Koran or sunna (the body of literature that includes the sayings and biography of the prophet).
The Ethiopians have done better, alongside a proxy force of Sufi Somalis known as the Ahlu Sunna Wal Jamaa (the Majority) or ASWJ, which now controls a wedge of land along the Ethiopian border.
Virtually all of these scholars agree that Muslim societies must accept Allah as the sovereign power and struggle to abide strictly by Shariah law as exemplified in the Sunna (the life, words and deeds of the Prophet).