I think this might be a good topic to discuss in the Christianity and society discussion forum, and I hope that Phil might write a kick-off article there, but I thought I'd put down some more personal thoughts here.
For me I suppose it started at a Biblical Studies lecture at university, when the lecturer talked about the "principalities and powers" of Ephesians 6 as if they were spiritual forces. I had assumed that "principalities" referred to places like Monaco, and "powers" referred to states like the USA, the USSR and so on. They were called "world powers" in newspapers, and the New Testament Greek kosmokratores seemed to be an exact equivalent. The lecturer exposed the limitations of my view by pointing out that St Paul had said that these powers were "in the heavenlies" and were not just earthly powers. He referred me to a book by G.B. Caird, Principalities and powers, which, he said, would explain all this.
I read Caird's book, and a couple of others on the topic, which dealt with the connection between Ephesians 6:10-12 and Romans 13:1-2, and began to look at other uses of the words archontes (rulers) and exousia (authority) in the Bible. This led to the Dionysian Nine, and a whole lot of things suddenly fell into place, including Charles Williams's novel The place of the lion, which I re-read with new eyes.
It also made sense of things like the Roman religion of emperor worship, and why Christian opposed the emperor cult, which was based on the idea that behind human authority was a spiritual authority, which could be recognised by its symbols, for our conflict is not against blood and flesh, but against the rulers, against the authorities, against spiritual wickedness in the heavenlies. A flesh and blood traffic cop who steps into a fast-moving stream of traffic wearing his pyjamas is likely to be ignored or run over. In his uniform, it is a different matter. It is not his flesh and blood that stops the traffic, but his authority. If he tried to stop a 26-wheeler with his flesh and blood, the result would be painful to behold. And the emperor cult did not involve worship of the flesh and blood emperor, but his genius, his authority. A couple of emperors did think they were divine in their flesh and blood, and most of their contemporaries recognised that they were nuts.
Passages like Deuteronomy 32:8-9 and Psalm 82 (LXX 81) suddenly made more sense in the light of this. There are such things as national spirits, and it is possible for a country to become demonised. The political struggle against apartheid was more than just a struggle against flesh and blood rulers. If the struggle were just against a Verwoerd, a Vorster or a Botha, then it should be possible to solve the problem by assassination - tyrannicide. But our struggle is not against blood and flesh, but against the rulers, the authorities...
Paolo Freire, the Brazilian educationist, put a new slant on this in his somewhat turgid book Pedagogy of the oppressed, when he said that oppression makes the oppressed feel less than human, and to the oppressed the oppressor seems more fully human. So the oppressed tends to internalise the spirit of the oppressor. When the oppressed overthrow the oppressors, they tend to become oppressors in turn. What needs to be overthrown is not so much the oppressor as oppression itself.
We saw a paradigm case of this in South Africa in 1976. Seventy years before, after the Anglo-Boer War, Alfred Lord Milner, the instigator of the war, tried to Anglicise the Afrikaners by forcing them to learn through the medium of English. Seventy years later Andries Treurnicht and Ferdi Hartzenberg tried to force black school kids to learn though the medium of Afrikaans. They had internalised the spirit of their ancestral oppressor, Milner. And the result was the Soweto riots, and the massacre of school kids.
What was needed was not so much the overthrow of the flesh and blood oppressors, as the exorcism of oppression. And that, of course, begins with me. It is not just Hartzenberg and Treurnicht who have internalised the spirit of the oppressor, but I have too. That is where the theological concept of nepsis (watchfulness) comes in. Spiritual warfare fought without nepsis and apatheia (dispassion) is apt to lead to prelest (spiritual delusion).
I wasn't much interested in exorcism of places until there were police riots in the Anglican Cathedral in Cape Town: police chased demonstrating students into the cathedral and beat them up inside. I asked the publications department of the Anglican Church if they had an exorcism service, and they sent me their entire stock, saying there had never been any demand for it. But I was disappointed to see that that service was only for the exorcism of persons, not places. I thought that after the police riots a public exorcism of the Cathedral would have been a good thing.
Are there territorial spirits? Is there a need for exorcism of places? I believe that there certainly has been a need for the exorcism of the White House and the Pentagon since the invasion of Iraq in 2003. There seems to have been no earthly reason for it, only an infernal one. And perhaps going back even further, to the bombing of Yugoslavia in 1999.
Going back further still, the break-up of Yugoslavia, and the wars of the Yugoslav succession, seemed to turn formerly good neighbours into demonised furies from hell.
This post is a bit scrappy and disconnected. It probably needs to be a lot longer to join the dots, but perhaps the last word can be given to G.B. Caird, from his Commentary on the Revelation of St John the Divine (Caird 1966:163-164), when writing about the beast from the abyss in Revelation 12:
But it must not be thought that John is writing off all civil government as an invention of the Devil. Whatever Satan may claim, the truth is that 'the Most High controls the sovereignty of the world and gives it to whom he wills' (Dan iv. 17). In the war between God and Satan, between good and evil, the state is one of the defences established by God to contain the powers of evil within bounds, part of the order which God the Creator had established in the midst of chaos (cf. Rom xiii. 1-7). But when men worship the state, according to it the absolute loyalty and obedience that are due not to Caesar but to God, then the state goes over to the Enemy. What Satan calls from the abyss is not government, but that abuse of government, the omnicompetent state. It is thus misleading to say that the monster is Rome, for it is both more and less: more, because Rome is only its latest embodiment; and less, because Rome is also, even among all the corruptions of idolatry, 'God's agent of punishment, for retribution on the offender' (Rom. 13. iv) .