When we outsiders see Boris Johnson stuck on a zip wire with a Union Jack in each hand or Jacob Rees-Mogg bringing his nanny along to canvass voters on his behalf, we are initially indulgent: how delightfully, comically, English. Photograph: EPA

When all of this is done – if indeed it ever is done – a question will puzzle historians. How did absurd characters like Boris Johnson, Jacob Rees-Mog(...)