Imagine a late 16th-Century European Kingdom. The King is obsessed with invading a small neighbouring country for no good reason. He would not profit neither economically nor politically.
However, his problem is that he can't decide on his own to go to war. He needs to put it to some assembly/government/council. And only if they agree, can the war be started. However the members of that assembly are reluctant to do so because it would be costly in financial and human terms, for no real profit.
Now, I am stuck at giving a body and legal status to that assembly. I am not a specialist of neither Magna Carta, nor the constituancy regime that was later implemented in England, but I believe none actually limited the power of the King such that he couldn't decide on going to war.
I can only think of two ways to block the King: economic council. Without money, the King cannot start the war, and he can't get enough money without the council approval. Military head of the army. If the head of the army refuse to go (that would be a first!) to war, the King would be blocked.
Do you think such an economic council could exist in the context? Who would be their members?
I'd appreciate alternatives as well, but it has to be realistic for the mentality of people of that time. Even better if you find historical references.