Post-Brexit Dreams of Global Britain Won’t Come Cheap

Theresa May last week set out her vision for Britain’s future trading relationship with the European Union. It was an overdue moment of clarity that may go some way toward unblocking stalled Brexit negotiations. But the U.K. Prime Minister has yet to provide any answer to a more fundamental question at the heart of Brexit: how does she see Britain’s future place in the world?

Brexiters insist that the decision to quit the EU was no act of isolationism or protectionism. They claim it was instead a vote for “global Britain”...