Give Brexiters a Millimeter, They'll Take a Mile - Bloomberg Opinion

But even taking all this into account, the scalpel wielded by the Commission -- lifting as much as half of customs checks and almost all sanitary checks on food imports, by its calculation -- could eventually risk cutting through the deal's fat and hitting muscle. Officials grumble of "blood on the floor" in bending rules. The EU risks sacrificing its own internal unity for the sake of the U.K.'s.

It is not enough for Brussels' technocrats to want to be the "adults in the room" at a time when the Brexiters are whipping up public opinion and eyeing divergence from data-protection rules.  At some point the U.K.'s bluff is going to have to be called. Leo Varadkar, Ireland's deputy prime minister, is taking a stab at this: On Wednesday, he leaped on tweets by Johnson's former aide Dominic Cummings supporting the idea that the U.K.'s aim was to go back on trade terms the moment they were signed. "The message must go out to all countries around the world that this is a British government that doesn't necessarily keep its word," he told RTE. If that means contingency planning for a tariff war, so be it.

The again, if the UK intends to trigger A16 in any case, it's won't matter that much. As Varadkar is warning us: contingency planning for a tariff war.