Could Australia and New Zealand Become One Nation?

The Australia Letter is a weekly newsletter from our Australia bureau. Sign up to get it by email. This week’s issue is written by Natasha Frost, a reporter in Melbourne.

Becoming a republic, legalizing same-sex marriage, changing the Constitution to establish an Aboriginal advisory body: To make these changes to Australian life requires — or has required — at least one nationwide vote.

Yet there is a far more dramatic step that could — but almost certainly will not — occur without…