Yes, it was, but evidence doesn’t work on most people with severe depression. The disease impairs the part of your brain that processes good news. Drag understood the evidence, but drag’s dragon couldn’t, because it was sick. That’s what depression is.
Imperialism - building an empire by exerting control over foreign powers
de jure - by law
cassus belli - cause for war
So conquering other places is okay when the law says you have a good reason to send soldiers marching down their streets?