I would say that King Charles did not deserve to be executed. It is important, however, to note that a large part of my answer is because I could not live with another person’s blood on my hands. Morally, I cannot accept sentencing another person to death. This might not be exactly what the question is looking for as a response, but it is a significant part of my reasoning.
I found the arguments on both sides of the issue to be compelling. I can see how the country would not be able to operate at all if they are constantly in fear of their leader undermining them and acting in his own best interest intead of the interests of his people. It is impossible to have a monarchy last very long if your ruler cannot be trusted. Furthermore, the harm he did to the country and his people was significant and cannot be overlooked. I can understand why it would be difficult to remain loyal to a king that devastates your country and potentially, more personally, your family. That is someone I would want gone immediately. I still do not, however, believe that he needs to be beheaded, but I can see that in those times that would be the realistic way of getting rid of a monarch.
To me, it was very telling that the process of his trial was hardly democratic and that few of the men nominated to the High Court of Justice actually attended the proceedings. It was difficult to get enough men to attend the proceedings and actually vote for him to be executed. Furthermore, the reaction of the crowd when he was beheaded was not that of people who viewed him as a traitor and the fact that people committed suicide because they felt so guily about sentencing him to execution speaks volumes. Though I think King Charles had proven a danger to his country, I do not believe the solution was a beheading
The question definitely invokes a debate of the morals of the participants involved in killing Charles. Similar to how many of us could not imagine sentencing someone to death, Charles himself had a very hard time imagining how his people had the right to put him to death. He believed that he was ordained by God, and died somewhat peacefully (again, somewhat) truly thinking that he was going to heaven and had done no wrong. The morals of all people involved in the conflict, and the morals of the people who analyze the conflict today, seem to differ greatly and make for great conversation.
I believe that Charles’ trial and execution was completely unfair especially because, like you said, only a few of the members of the High Court of Justice actually attended the meetings. This is a very difficult question to ask and makes one truly look at their morals. It isn’t right to kill someone however, with how much his people did not trust him being their king, it makes sense why they felt as though this was the only option they had, especially in that century.