Name: Jim “Mad Dog” Mattis.

Age: 67.

Appearance: Small, bookish, silver-haired killing machine.

Occupation: United States secretary of defense.

Hobby: Trump whisperer.

That’s handy. We need a few of those. Yes. And it seems that Mattis, a retired Marine Corps general, is the best around. Trump has sacked or insulted just about all his other appointees, but Mattis clings on, and even counteracts the president’s worst instincts.

How? Well, according to Bob Woodward’s forthcoming book on the Trump White House, Mattis follows the president’s orders very slowly, until Trump forgets he made them, or calms down.

For example? Last April, after the Syrian chemical attack, Trump reportedly rang Mattis and insisted that they should assassinate Bashar al-Assad. According to Woodward, Mattis put the phone down and told an aide: “We’re not going to do any of that.” Instead, he prepared for an air strike on Syrian military positions, which Trump later approved.

That doesn’t sound very, how should I put this, democratically correct? No. Woodward calls it an “administrative coup d’etat”. Apparently the former chief economic adviser, Gary Cohn, once sneaked a letter off Trump’s desk before he signed it. It would have withdrawn the US from a trade agreement with South Korea, but Trump never noticed it had gone.

But now Cohn’s gone? That’s right. Along with Flynn, Comey, Corallo, Spicer, Priebus, Scaramucci …

All right. I get the picture. … Bannon, Gorka, McCabe, McEntee, Tillerson, Dowd …

Enough! … Hicks, McMaster, Cobb, Pruitt and many others. Yet Mattis is still there, despite disagreeing with Trump on the Paris climate change accord, the Iran nuclear deal, tariffs, transgender people in the military and moving the US embassy to Jerusalem.

What is his secret weapon? He had a distinguished military career and he talks about as bluntly as his boss.

How is that possible? By saying things like: “Be polite, be professional, but have a plan to kill everybody you meet.” Or: “There are some assholes in the world that just need to be shot.” Or: “It’s fun to shoot some people.” Apparently Trump loves that kind of stuff. And, of course, Mattis never criticises his boss in public.

Always a good plan. What a pity this book has come out. It will ruin everything. Only if Trump believes it, which he has said he does not. Mattis also insists he never used the “contemptuous words” in the book, adding wryly that “I generally enjoy reading fiction”.

Phew. So everything is fine, then. I wouldn’t go that far.

Do say: Have a biscuit, Mr President. You always want to bomb Tehran when you’re hungry.

Don’t say: Let’s go with “Sane Dog” from now on.