What is the principle of Nothing About You Without You?

What is the principle of nothing about you without you?

The United States, its NATO allies, and European partners are fully committed to the principle of nothing about you without you, that is to say, nothing about NATO without NATO, nothing about Europe without Europe, and nothing about Ukraine without Ukraine.

Two young boys on an Ariel motorbike, National Park, Sydney, 1940 | State Library of New South Wales