fdr - Thank you for that.
Too much dependant on the security council, however.......
I think Article 51 covers it...
Nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations, until the Security Council has taken measures necessary to maintain international peace and security.
As I read it, anyone can invoke Article 51 and come to the aid of Ukraine (
collective self-defence) without a directive from the security council. I think the Poles will get there first, they have a lot of scores to settle with Russia.