I see.

So the best day to invade the UK or a Commonwealth country - with the purpose of disrupting command-and-control systems - is Election Day (not the day before or the day after).

OTOH, in a pinch, Her Majesty (or Her Guv-General rep) always has the option of donning Her helmet, grabbing her sword and announcing "To Arms!" in an emergency.

Neat.

Over here the best invasion day might be the day after Inauguration Day. The new guys haven't even found their way to their offices yet, and the old guys have returned to their homes.