A theocracy means rule by God or gods, with a priestly caste doing the actual ruling. In medieval times the Catholic Church proclaimed superiority over the spiritual life of all Christians, not temporal affairs, which were the domain of the king (in the Papal States they administered both, but even there they were separated into different fields). Often they clashed with the worldly powers of the state, as with the long-running feuds between the Papacy and the Holy Roman Emperors or the kings of France and England.
The church was in charge of temporal affairs. The church created laws, the Pope divided up the new world between the Spanish and Portuguese. European states were weak back then.
He could declare it, could he enforce it?
Take the First Crusade, declared by Pope Urban II. He could not simply order up the armies of Christendom, he had to persuade Kings and nobles to join, and offer incentives by giving indulgences (free passage to Heaven) to those who took the Crusader cross.
Many responded enthusiastically, some offered younger brothers and second sons who were beginning to look a little too ambitious (Hey, look! Free land for the conquest), some politely ignored it, having their own fish to fry closer to home. Point was, the Pope couldn’t order anybody to go, he had to persuade, stir things up by rhetoric, and bribe (by spiritual means)feudal lords to go.
As for the Treaty of Tordesillas, it was part of a long series of clashes between two Catholic powers, and the Papacy was an arbitrator running back and forth between the two- and was completely ignored by the rising Protestant powers of England and the Netherlands.
This a very Americanised view. Doing things the American way isn’t necessary and probably wise not to follow.
Australia for example does not have Declaration of Independence nor a bill of rights but clearly has rule of law and is cautious not to infringe the people’s freedom of religion/not having a religion.
But based on the following comments it seems that secular states are more likely to have rule of law and the US has questionable secularism
What if I don’t give a flying damn about them and actually get offended if an institution of the State is trying to force me to follow something I don’t want or care and that is actually not codified into law, like religion? So long freedom right?
I don’t agree with the theocracy enabled rule of law theory at all. The real beginnings to rule of law was nobles gaining enough power to force the throne to agree to the Magna Carta. That is followed up by the upper and middle classes being able to participate in parliament.
I would say there are 3 criteria for rule of law.
A law making body where members aren’t appointed, but elected in some form.
An independent judicial branch separate from executive and legislative branches.
A military loyal to the constitution and not a leader or party.
For China, I think never has all 3 been true at the same time.