We understood and accept that the West is crummy from the word caliphate, where Islam cannot be separated from the state. On the other hand, Muslims no longer know that how a caliphate system should be properly operated in today’s conditions. One thing is for sure: only with the Quran in hand, it cannot be. The well-functioning caliphates of history (Andalusia, Baghdad) merged within themselves the knowledge of the age, they were enlightened, civilized forms of state, where positions were divided not on the basis of religious affiliation but on the basis of expertise. This era ends in Iberia in 1492 and in Baghdad in 1258. In subsequent caliphates, the need for power overwrote the principles of Islam. Therefore, I don't cry to get them back.
In the Sharia-based interpretation, there are three types of administration: secular, civil, and religious. There is no religious state today. Nominally, the Vatican is a religious state, Israel was also created by reference to religion, but I think it is clear to everyone that none of them operate on a religious basis. There is also no religious state on the Islamic side as well and the conditions are not available for that.

Behold, thy Lord said to the angels: "I will create a vicegerent on earth." They said: "Wilt Thou place therein one who will make mischief therein and shed blood? - whilst we do celebrate Thy praises and glorify Thy holy (name)?" He said: "I know what ye know not." (Quran 2:30)

This is about the creature of Adam and earthly life. In the Unseen World there are inhabitants, too. They are the Jinns and Angels. A conversation begins between Allah and the Angels where Allah declares His will to create vicegerent (Caliph) on Earth. The Arabic word “Khalipha” means a person who is a representative or follower. This word also expresses subordination under the One Who has to be represented and followed. Angels were doubted about the advent of any creation in the Visible World who is able to realize this mission with responsibility without being selfish what leads him to the side of sins. This is a Biblical forecast of the future by the Angels. However, this is only a forecast by them but Allah knows what is going to happen and what will come at the end.

These “Vicegerents” quoted in the Quran and a state that could be built on them in an absolute sense, don't exist today, nor will they be, as they were the Prophets. Since we believe that Muhammad (peace be upon him) was the last prophet, no other will come after him, so the caliphate institution in the public consciousness cannot be considered a purely Islamic form of state either. They were civil states where legislation was built on the principles of Islam, but was governed by humans, with their own virtues and faults.
What, then, is the secular state from our point of view? A state where the people, i.e. the parliament takes decision. In the constitution of a secular state, the power of the people is confirmed in many places, as if they were afraid that someone would take power away from the people if this was not emphasized. On the other hand, the people, so parliament, can take decision about everything. Can Parliament decide on the right of homosexuals to marry? Yes, it can decide. (Don’t misunderstand! I'm talking about the right of parliament and not about the right of homosexuals!) Can Parliament decide on the possibility of abortion? Yes, it can decide. Can Parliament decide the issue of war and peace? Yes, it can decide. There is no upper limit for parliament, it can decide everything! Even humans take decision if, nominally, the Constitutional Court draws the final boundaries above the parliament. At this point, the Sharia draws the line! But this sort of Sharia does not exist today because it has not been modernized since the Middle Ages. The one in public consciousness is not harmonized with age and norms. For if it existed, the principles of Islam would set the limits within which man is free to take decisions. No tree grows until the sky and even though horseradish or beet roots store plenty of food, their leaves don’t grow bigger than they need to be. The law of the upper limit works properly in the earthly creation. Can there be an interface where the two principles meet?
Yes, it can exist. Of course, this requires thinkers on every side, of whom there are fewer and fewer.
Let's assume that the wish for reconciliation what is impossible to imagine today, once comes true. If such an age were to emerge, it would, in principle, be satisfactory for all to have a civil state where, in addition to the existing rights of freedoms, which are very important, there would also be ceilings. The moral limits of man must, indeed, be limited by existing Divine laws, and our Scriptures do not differ much in these principles. The boundary cannot be crossed by a decision related to interests, identity, the pursuit for power, and harm caused to the creation. This would be the state where democracy would have an upper limit and this is not defined by humans.