“Overthrowing your leaders is addictive,” says Jonn Elledge in The New Statesman. Just look at the Roman Empire. The Praetorian Guard assassinated one “incompetent young emperor” in AD 222, the army another in AD 235. This set a bloody trend: in half a century, the empire ran through about 26 leaders, “only one fewer than the number who ruled in the previous 262 years”. The people who really held power, the military, had suddenly realised that they could “make or break emperors pretty much at will”. If they didn’t like one, they’d kill him and appoint another.
This is “an extreme example of a surprisingly common pattern”: those in the lower ranks “discover, to their surprise, that they can oust a leader and, unable to achieve much else, they do so, over and over again”. It happened in 15th-century England with the Wars of the Roses; it’s happening in modern Australia, which has had six prime ministers since 2007. And it’s happening in the Tory Party today, which has had four leaders in six years. That’s why, despite Liz Truss’s newness as PM, her security in the job is far from assured – her party has got accustomed to “the nuclear option” when things go badly.