Reimagining the Anglosphere

The United Kingdom’s messy exit from the European Union might not lend itself to the suggestion that London joined another supranational body. But Western unity is more important now than at any other point since the Cold War. Given that the U.K. and the U.S. already have their long established “special relationship,” and that both nations enjoy good relations with the rest of the developed Anglosphere, it’s worth considering what a free movement zone with Canada, Australia, and New Zealand (CANZUK-US) would look like.
How would a free movement zone work?
CANZUK-US would more or less copy one of the “four freedoms” that comes with being a member of the European Union: Any EU citizen can travel to any other country in the union to visit, study, or work without a visa. Moving from one EU country to another is, legally speaking, no more difficult than moving from one U.S. state to another.
A free movement zone would mean that citizens of the CANZUK-US countries would need to present only their passports to enter other countries in the zone, after which they would be allowed to stay for however long they wanted for any reason, so long as they register with authorities and pay any tax liabilities they incur (just as citizens already living in that country do).