Tell us, do you get your knowledge of history from Jack Chick tracts?
Is that the best you can do?
No one I know of says Calvin was right here. That is NOT the same as idiotically accusing him of being a bloody tyrant. The idea of the church being separate from the state was novel, and it is silly to accuse Calvin of not being born 200 years after he was.
The bible is largely silent on the "correct" formulation of a state for those in the New Testament. I have read the arguments by Rushdoony and Bahnsen (RIP) for a theonomic state. While some points are valid, I don't buy them. HOWEVER, the idea that the state is to enforce the 10 words (including what is called the "first table") was a commonly held viewpoint of the day. To act with feigned horror that someone would not take a position of John Locke, when Locke was born over a century later, is idiocy.
That is what I meant by Calvin being "a man of his time." The union of church and state was assumed to be the way it is, and theologians looked to the City of God as being expressed in its political and legal spheres in the city of men. Civil codes since Augustine reflected this ideal.
Do I then agree with the execution of Servetus? No. I think that the scripture is largely silent on the role of the state, save that it should be an "agent of wrath" to those who do evil. The nature and extent of that evil is not defined for us. I do believe the boundaries of restraint are to be wide, and should allow for heresy.
However, it is stupid cant and hypocritical moral posturing to argue that Calvin's failure (and I do believe it was a failure, as some of his contemporaries did) makes him some kind of bloody tyrant, delighting in using the sword to establish his own power.
Calvin had long correspondence with Servetus, who reminds me of some of the trolls on any bulletin board. He was hateful, insulting, blasphemous, and worst of all, he just did not know how to shut the hell up. Calvin quit answering him after a while, and Servetus continued to rant and send him tons of the most hateful and idiotic stuff. Calvin essentially said to a colleague that this kind of rant would be killed if he came to Geneva. He told Servetus this in a letter, warning him not to come there. So, the first thing he does is show up at one of Calvin's sermons, after taking a detour to Geneva to do so.
Does the brain dead obstreporous, idiotic, galling belligerent stupidity of Servetus EXCUSE Calvin? I don't think so. But neither is it reasonable to paint some imbecilic picture of Calvin chasing him with a flame thrower through the streets of Geneva.
It is interesting that Calvin met with him, prayed with and for him, and urged him to commit his soul to the God whom he had blasphemed. Calvin was NOT a hater of Servetus. He told him he did NOT hate him nor had any desire to persecute him. He stated that his opposition to him ("hard as iron") came from his fear of the damage Servetus's views would do to the church.