The recent attempt on Donald Trump’s life has invited scrutiny of the Secret Service. It looks increasingly likely that Trump’s security detail left him vulnerable to an assassin’s bullet, thanks to complacency, miscommunication, incompetence — or all three.

Still, not all of the blame can be laid at the feet of the Secret Service.

The job of protecting the president has long posed an extraordinary challenge. For over two hundred years, our chief executives have doggedly insisted on putting themselves in danger by mingling with ordinary citizens. This has led to an unfortunate statistic: roughly a quarter of all presidents have been victims of serious assassination attempts — four of which ended in death.