Must we trigger Article 127 if we want to leave the single market?

The dark and dusty corners of the internet aren’t wholly taken over by climate change deniers and crush videos. Constitutional lawyers have one too. And of late it’s been consumed with the Norwegian option.

In case you’ve forgotten—and I rather hope you have—Norway is part of the European Economic Area. It’s a kind of single market hinterland where the “four freedoms” apply—including free movement of persons (and you still make contributions to…