Complex sentence: It also states that the Shinto religion had always been, and that the Japanese people had always believed, an ideology preaching world domination and fascism--in fact the militarist brand of Shinto was a comparatively recent development.
Split into simpler sentences: It also states that the Shinto religion had always been, and that the Japanese people have always believed, an ideology preaching world domination and fascism. In fact, the militarist brand of Shinto was a comparatively recent development.