Why the resignation of US Defence Secretary Jim Mattis could be the least of Donald Trump's problems

The man nicknamed Mad Dog Mattis was seen as a cool head in the Trump administration. Credit: PA

The resignation of US Defence Secretary Jim Mattis is a protest that will be heard around the world.

The former General was widely regarded - despite his colourful nickname of Mad Dog - as the most measured and thoughtful leader in the Trump orbit.

Who now can European allies turn to when they need a friend in Washington? (You guessed it: there’s no one left that they trust).

Mattis’ resignation letter was a spectacular rejection of the President’s worldview and sends a warning shot not so much over the White House as straight into the Oval Office.

The defence secretary was clearly appalled at the decision-making over Syria.

He fears that a precipitous withdrawal of US troops abandons Kurdish allies, humiliates NATO friends, and emboldens Tehran, Damascus, Ankara and Moscow.

The metaphor being used most frequently by analysts and retired generals is that the wheels are finally coming off.

It is partly because of Mattis’ departure, but it goes beyond that.

Trump is poised today to announce - no doubt on Twitter - a major troop withdrawal from Afghanistan as well.

That also will be vehemently opposed by Republican senators who see Trump as surrendering costly gains and creating a dangerous vacuum in some of the least stable places on the planet.

Sorry, this content isn't available on your device.

In addition, there is a toxic political confrontation underway over a spending bill that may - or may not - fund Trump’s signature issue, the Mexican border wall.

If Congress fails to fund the Wall then Trump is threatening to shut down the government.

That’s right - over Christmas and the New Year, America will be paralysed.

One TV network put on screen its headline for the night. It read simply: “Trump chaos: Mattis Out; Shutdown Looming; Stocks Plunging; Department of Justice in Turmoil.”

That succinctly sums up where we are.

And, oh yes, there are reports that the Mueller Investigation will be ready within the next eight weeks.

Perhaps Christmas will be cancelled too, and then we really will have the perfect storm on our hands.