So, the US Secret Service is informed of a credible threat to Air Force One, moves President Trump to another aircraft, and lets Air Force One depart, effectively as a decoy. This happened last month as the President departed Ankara after a NATO meeting. Now the word is out, and some precious souls in the press corps are aghast.Typical is Esquire’s Charles Pierce, no fan of President Trump to begin with, who writes, “Okay, the part to be angry about is that he used some of his own staff and some people in my business to save his own desiccated hide.”Buttercups all. As a “working journalist since 1976,” writes Pierce (is there another kind?), he knows the drill. Looking after the boss is always job one.Same thing north of the border, where the PMPD (Prime Minister’s Protective Detail) is the RCMP's specialized unit responsible for the continuous, 24/7 close protection of Canada’s prime minister and immediate family, in Canada and while travelling abroad. They are tough, friendly, and cool in hot temperatures.So let me tell you a story about the only time in the six years I wrote speeches for Stephen Harper that I ever saw these guys get the wind up.It was August 2011. We, the taxpayers of Canada, had paid for the Soacha Youth Development Centre in a “municipality” on the southern outskirts of Bogotá. Stephen Harper, Prime Minister of Canada at the time, wanted to have a look at what we had done there. As speechwriter, I was along for the ride..Soacha was not a place you'd want to live or even go to. Widely regarded as one of Bogotá’s poorest and most troubled areas, it was, and apparently remains, marked by informal settlements, displacement, and high social need.To get to this youth club, there was one road in. When we were done there, it was the same road out. No side roads, no turnoffs. In other words, our motorcade was highly vulnerable to an ambush, should anybody want to try it.The Colombians knew that. They had stationed armed police every 150 feet or so for the entire mile and a half from the Soacha turnoff to the youth club.I remarked upon this to a member of the PMPD. “What’s the plan if this goes wrong?”He said I shouldn’t worry; there was also a helicopter overhead to airlift the PM out at the first sign of trouble.“And the rest of us?”Police humour: “If you can’t take the joke, don’t take the ride.”.In other words, they do their best, but in the end, staff — and it should be recognized, the PMPD and, in the US, the Secret Service themselves — are considered expendable.Which is certainly the case if you’re travelling with a US president. As a journalist, you’re welcome to come for the ride. Aboard Air Force One, you will dine well, travel in comfort, and later bask in the reflected glory of great events. Your friends are impressed, and you are free to ask rude questions to the most powerful man in the world and equally free thereafter to write rude things about him..But if push comes to shove, he’s the guy the Secret Service is there to look after. Same everywhere, and absolutely the same for the Prime Minister of Canada.Anyway, nothing happened on our little walk on the wild side. The PM admired the facility, read stories to children for ten minutes, and we went out the way we came in. People were waving Canadian flags and having fun. But until we got out of Soacha, the PMPD were watching them like hawks looking for voles in long grass.Critics call the Ankara Trump switch reckless endangerment of non-combatants. Perhaps they have a point about the optics and the trust. But security details do not exist to manage optics or trust. They exist to keep one specific human being alive long enough for the constitutional order to continue. When the threat is judged real and imminent, the hierarchy of protection is absolute. The press pool is not the principal. Neither are the junior staffers who stayed on the big plane. The man the electorate chose is.That is not a moral failing of the Secret Service (or in Canada, the PMPD). It is the entire point of their existence. Looking after the boss remains Job One. On both sides of the border, the rest is secondary, and always has been.