Although these fine citizens appear to have been of the meth-fueled neo-"Odinist" a self proclaimed Nordic Pagan persuasion, historically, most "white supremacist"
bombings can be fairly directly tied to a cult who call themselves "Christian Identity" (emphasis on quotation marks, intending no offense to Christians).
Unlike most Christians, "Identity" types believe that Jesus was of Anglo heritage, and that Jewish people are literally not human, but the spawn of Eve and the Serpent. They likewise believe that non-caucasians are not human either.
The ultra-violent "Christian Identity" types use bombing as their preferred method of crimes against both persons and property
This is one of the most fascinating books I have ever read, and I highly recommend it to anyone who is interested on what is actually behind a lot of the most violent "white supremacy" activity from the 1950s up until today:
Nonfiction Book Review: America
Please do not get curious and go around googling "Christian Identity". The material out there available online is highly offensive, and potentially dangerous, to just about anybody and everybody. I'm just glad the author of that book did all the research he did. The book is outstandingly thorough, even-handed, and well annotated.