In ancient times, Kings and Emperors were sovereigns. They were not accountable to anyone, they could make and pass any law which they thought fit. They were the last resort for justice or for any other matter and their decisions were final.
With the rise of democratic Europe sovereignty shifted from the King Emperor to the representative assembly of politicians. In most countries it was the Parliament which became sovereign having the power to make laws for the people without being accountable to anyone else. This worked quite well in nation-states based on secular parliamentary democracy or representative politics (as in US).
It was however a big blow for Islamic states which were formerly part of an Islamic super state, the Ottoman Caliphate. Concepts of nation-states and secular democracy were alien to post WWI newly independent Muslim countries. For them, sovereignty was for Allah swt only. In an Islamic state everybody, including the Chief Judge or the Prime Minister, must surrender to God’s laws, being accountable to God for all their actions. People are not free to change the value system as law makers.
Till date, we see most Muslim countries struggling with these western concepts of nation-state sovereignty and secular democracy. Muslims can’t reconcile these concepts with Islamic concepts of accountability, submission and universalism. From the Holy Quran,
Say, “O Allah , Owner of Sovereignty, You give sovereignty to whom You will and You take sovereignty away from whom You will. You honor whom You will and You humble whom You will. In Your hand is [all] good. Indeed, You are over all things competent. (TMQ 3:26)