OTTAWA — The boundary between Canada and the United States runs 8,891 kilometres and has for generations been described in official prose as the longest undefended border in the world. This week the description acquired a maintenance schedule. Prime Minister Mark Carney confirmed that the Canadian Armed Forces are running scenarios for an event he classes as unlikely: an invasion of Canada by the United States. The adjective and the scenarios are now both official. I have filed them together.

Both statements proceed from the same government, in the same capital, within the same season. The first holds that the border is undefended. The second holds that the border may require defending against its southern neighbour. Locals detect no contradiction; the species applies planned aesthetic obsolescence to clothing and calls the practice fashion, and the adjective “undefended” appears to have enrolled in the same programme — retired from function, retained for display. The distance between briefing and event is normally measured in hours. Here my instruments return one adjective.

“The scenarios are precautionary and, we emphasise, unlikely,” said Deirdre Kowalczyk, Deputy Director of Continental Scenario Modelling at National Defence Headquarters. “The border remains undefended in every document a visitor is likely to read. The two positions coexist without friction because they are stored in separate binders.”

“The adjective is load-bearing,” said Martin Bélanger, Communications Director of the Cross-Border Tourism Consortium. “Remove undefended and the sentence survives, but the coach tours do not. Nobody crosses a famous adjective to inspect a planning cell.”

Mr Carney arrives prepared. Before entering politics he administered two institutions licensed to store numbers, in Ottawa and London, and is thus practised in assuring depositors that their numbers are stationary while quietly planning for them not to be. A planning cell, in local practice, is where an unlikely event is kept until it becomes a schedule. No date for the invasion has been published, which both sides of the border appear to find reassuring.

Adjective: retained. Scenarios: active. Invasion: unlikely. Reconciliation of the two statements: not scheduled.