Boris Johnson is best viewed as a kind of institutional solvent. Every institution he has been let near, he has weakened. Every norm he has encountered, he has transgressed. His crime was not that he was incompetent. Many before him have been worse. His crime was that he fundamentally didn’t care about the offices he held. Most political stories end in failure. Like Silvio Berlusconi before him, Johnson’s political demise was always going to end in shame. From Trump to Bolsanaro to Johnson, the point is now pretty well made: Politics is serious business, and showmen are not cut out…