In 1947, the highest court in our land, the Supreme Court, interpreted the 1st Amendment of the Constitution as creating a: "… wall of separation between church and state." While this inexplicable decision has had mostly negative consequences within America, there is one bright side to the forced and legal separation of Church and State in our country, which is, when State power and Church power are combined into one solidified entity, the people are for a certainty, under the thumb of total despotism, with no recourse to either State or God for relief, as the State as God, holds not only all physical power over the servants of the State, but absolute spiritual power as well.
In history, there have been numerous empires, combining the power of Church and State as one, to which, two of the most intriguing examples are Napoleon Bonaparte and King Henry VIII. In regards to France, the country's religion was Catholic, however, the power of the Pope was contained within the Papal State located in Italy, so that for any Emperor, in any country, there was going to be, as there was, an uneasiness between Church and State, especially when that Church has influence over the subjects of your empire, and in addition to that influence, that Church has representatives within your sovereign nation, and, as part of Church policy and purpose, was able to extract what could be considered to be "tribute" to the Church's coffers as well as having control of valued properties within France. Thereby, when it came time for the coronation of Napoleon, at the Notre Dame Cathedral, Napoleon himself, conferred the crown upon himself, as opposed to the Pope doing so, signifying, that this Emperor, did not need bow to the spiritual authority of the Papal State. Additionally, to drive home further the point, that Napoleon, as opposed to the Pope, had the force and military might to do as he wished, Napoleon, held Pope Pius VII prisoner for nearly five years. This imprisoning of the Pope was not done so as to destroy Catholicism, or to abolish Catholicism, but to bend Catholicism to the purposes of the Emperor, so that in effect, the Papacy would be enthralled to Napoleon.
As for King Henry VIII, being unable to sire a male born child with his wife, Caroline, he desired to annul his marriage, but in order to do so, as a loyal subject and Defender of the Faith of the Holy Roman Church, he would have to get authorization for this annulment via the Pope, which did not occur. This decision by the Pope, led to King Henry VIII in conjunction with his court, coming to a determination, that the ouster of Catholicism from England, would not only permit the King to divorce, but also would allow the redistribution of lands and properties owned and/or managed by the Catholic church and its representatives, to being replaced by favored court representatives. Thereupon, King Henry VIII formally broke from the Catholic Church, declared himself instead to be head of the newly created Church of England, and thereby combined both Kingly as well as priestly powers into one hand.
The lure of both earthly as well as being the authorized representative of Godly power is the type of combination that tyrants have turned to again and again, so that they, as opposed to the people, control both the physical, as well as the spiritual, and hence, leave no respite or sanctuary for their people to oppose their avarice.