> why Russia should be permitted to invade Ukraine
That's awkward language. Who gets to grant permission for the invasion of a foreign country?
The question is whether it's legitimate to go to war against the invader. NATO is not a schoolmaster, issuing invasion passes. Unfortunately NATO doesn't have clean hands (Libya, and arguably Iraq).
I guess the UN could pass a resolution to authorize an invasion (though they can't really enforce anything). It's why the US presented their case against Iraq to the UN 20 years ago.
Though in this particular case, the demands Putin made before the invasion, that NATO should promise never to allow Ukraine in, and should abandon eastern Europe entirely, sounded a lot to me like Putin was basically demanding permission to invade those countries.
Because while NATO can't give permission to invade, it can most certainly enforce a denial of that permission by defending the target of the invasion. And that's what Putin was asking from NATO: a promise not to defend Ukraine or any other country in eastern Europe.
Kinda, but if I'm not mistaken, a military intervention can be declared necessary in cases of genocide, for example. It's not clear whether WMDs would count, but that was Bush's case for the invasion of Iraq.
That's awkward language. Who gets to grant permission for the invasion of a foreign country?
The question is whether it's legitimate to go to war against the invader. NATO is not a schoolmaster, issuing invasion passes. Unfortunately NATO doesn't have clean hands (Libya, and arguably Iraq).