What CANZUK would add to existing defence relationships

What practical benefit would CANZUK provide beyond the relationships Canada, Australia, New Zealand, and the United Kingdom already have?

Its advocates need to identify a distinct goal, because NATO, Five Eyes, AUKUS, and existing bilateral ties already provide much of the proposed defence and intelligence cooperation.

CANZUK advocates are asked to define the additional institution they want instead of treating the name as an end in itself. Canada, Australia, New Zealand, and the United Kingdom already overlap through NATO, Five Eyes, AUKUS, and close bilateral relationships, often with the United States included. A new defence or intelligence structure would therefore need to provide a function that those arrangements do not already perform. The practical test is whether an alliance adds obligations or capabilities that its label alone cannot supply.