You get "preemptive self defense" that urgently requires "buffer zones" on foreign territory, which then mysteriously become your own territory and have to be defended with even more buffer zones.
Some Terror Regime of Literal Nazis is doing Unspeakable Atrocities to its own population which practically forces you to invade the country purely out of empathy and the goodness of your heart. Nevermind that the population has never asked for the invasion and will in fact be worse off through the war than before - and that this other state who is your ally is doing the exact same things, but then it's suddenly "realpolitik" and just the way the world works.
Someone has broken the law of his own country. "Internal affairs" or grounds for invasion? Depends if he is your ally or enemy.
Pardon the cynicism, but my growing impression is that war justifications only serve as discussion fodder for domestic audiences and have very little to do with the actual war.
