The essay below highlights the dangers of rushing to judgment. The best quote from the article is: "Meanwhile, the deputy police chief announced that the shooter was a “Christian fundamentalist” but no one has reported either the evidence for the claim or how the police determined that. Whatever the case, he may be the only Freemason, Rome-leaning, Protestant fundamentalist in the world." Here's a link to the article.
UPDATE: here's a particularly salient comment following the op/ed.
The Atlantic has this terrorist all figured out » GetReligion:
I do think the “fundamentalist” angle taken on this story is off-base. Breivik’s Christianity appears to be of a cultural kind - Christianity as the religion of opposition to Islam & “cultural Marxism.” He wrote this book under the pseudonym “Andrew Berwick.” I certainly haven’t read the whole thing; it’s incredibly long at 1511 pages. Page 1309 has some interesting bits on the Christian angle:
A majority of so called agnostics and atheists in Europe are cultural conservative Christians without even knowing it. So what is the difference between cultural Christians and religious Christians?
If you have a personal relationship with Jesus Christ and God then you are a religious Christian. Myself and many more like me do not necessarily have a personal relationship with Jesus Christ and God. We do however believe in Christianity as a cultural, social, identity and moral platform. This makes us Christian. …
European Christendom and the cross will be the symbol in which every cultural conservative can unite under in our common defence. It should serve as the uniting symbol for all Europeans whether they are agnostic or atheists.
The pacifist/suicidal Christians must never be allowed to dominate the church again which one of the reasons why I personally believe that the protestant Church in Europe should once again should reform to become Catholic (Nordic countries, the UK, Germany, Benelux etc). Re-introduction of cultural and Church aspects relating to honour should be the core of our objective when reforming the Church. My hope is that the future nationalist leadership in Western European countries will agree. At the very least, we must support the conservative, anti-pacifist cultural Christian leaders and ensure that they are able to influence the European churches. There must however be clear distinctions. The Church must not put any limits whatsoever on issues relating to science, research and development. Europe will continue to be the world’s center for research and development in all areas, strengthened by a predictable and “unchangeable” cultural framework. This again will considerably strengthen European and societal cohesion and therefore contribute to sustainable societies where harmony, progress, freedom and the furtherance of mankind are the primary civilisational pillars.
There’s also a lengthy interview with Breivik beginning p. 1351 that reveals many of his ideas about “Christianity.”

