The Trump Doctrine on foreign affairs, inasmuch as this gut-instinct president can be said to have a consistent ideology, has been a relatively consistent part of this presidency. It’s been a doctrine more in line with those on the left than most in his own Republican Party, one that seeks to reclaim America’s more isolationist traditions. That is, until now.

His decision to assassinate Iran’s Qassem Suleimani stands at odds with his choices as Commander-in-Chief through much of his first term and what had seemed to be a relatively isolationist approach to military conflict around the world.

While Trump has not had the grand strategies or clear names like a ‘new world order’ or ‘Pacific pivot’, you can argue that his line on world affairs has been pretty consistent. In short, if it’s not about making American great, he doesn’t really care that much. He doesn’t want to get drawn into other people’s wars, he doesn’t want ‘boots on the ground’, he wants others to fight their own battles (see his NATO stance).

Ironically, given he is everything else the Left hates in a president, his limited use of the military and withdrawal from warzones has been consistent with many critics of previous Republican presidents have long called for. Trump’s presidency has been marked by his consistent refusal to get drawn into military conflict. The man who sees himself as the world’s greatest dealmaker has always erred on the side of wanting to meet and talk or impose sanctions rather than send in the troops or drones. The line has very blatantly been “America First” and “The job of our military is not to police the world.”

He’s taken almost the opposite approach to Teddy Roosevelt’s famous dictum to ‘speak softly and carry a big stick’. Well. he’s carried a big stick – with increased military spending – he’s tried to achieve deterrence without actually using it.

Trump has tweeted all caps, but been reluctant to strike with force, even against his biggest bogeyman, Iran. He’s pulled troops out of the conflict zones in Syria and Afghanistan and left other allies to their own devices.

He’s a million miles from the likes of Harry Truman or either George Bush, who wanted to export democracy and support sympathetic governments around the world. Heck, this is a president with a fondness for dictators.

In business-speak, he’s narrowed America’s focus to a few core products (China, North Korea, Iran) and stopped expansion into other areas. He’s got back to what might be considered core foreign policy business, rather than trying to be all things to all countries. He’s stopped trying to be the Kmart of world diplomacy.

As a man who likes to win, as recently as last October he said, “When we commit American troops to battle, we must do so only when a vital national interest is at stake and when we have a clear objective, a plan for victory, and a path out of conflict.”

I’d note that the ‘vital national interest’ line is arguably why Saudi Arabia is such an exception to Trump’s rule. Oil still matters. Israel? That’s about politics and re-election.

That approach is sensitive to the criticism Presidents Obama, Bush Jr and Bush Sr received for their more interventionist approaches to conflict overseas.

Iran seemed to have noted his hands-off approach and in the past year had sought to exploit it. This piece from the New York Times in September points out how Trump has resisted calls for strong actions after tankers were attacked, a British ship seized, a US drone shot down and even Saudi oil processing plants blown up.

In the months before the attack, Trump recoiled from using the military to send a message to Iran for shooting down the drone. He unsuccessfully sought a one-on-one meeting with Iran’s president. He fired his hawkish national security adviser. He even pondered ways to relieve Iran from the pressure of the very sanctions he imposed.

The column’s author, Bret Stephens, wrote:

In the months before the attack, Trump recoiled from using the military to send a message to Iran for shooting down the drone. He unsuccessfully sought a one-on-one meeting with Iran’s president. He fired his hawkish national security adviser. He even pondered ways to relieve Iran from the pressure of the very sanctions he imposed.

These are not the actions of a leader spoiling for a fight. Iran’s increasingly bellicose behavior is less of a response to U.S. economic pressure than it is an assessment of U.S. strategic will. Trump’s transparent hankering for a deal gives Tehran an opportunity to aggravate the crisis — all the better to extract favorable terms in a negotiation.

It seems, however, we now see there is a line for Trump and Iran is seen to have crossed it. Whether he sees political value for re-election this year (a risky move to say the least) or he now sees American interests directly in peril, it’s hard to say. Some have argued it is just in Trump’s character to want to look macho, although his restraint on other occasions undermines that angle.

Whatever the reason, Trump is now sending more troops into the Middle East and has put American interests under threat of reprisal, something that seems to be completely at odds with his doctrine so far and risks dragging the US into the sorts of wars he has longed mocked.

No-one wants war in the Middle East right now. No-one has much to gain from wider conflict, and maybe the Trump administration is banking on that. Even Benjamin Netanyahu has distanced himself from the assassination of Suleimani, ironically saying that he doesn’t want to get “dragged into it”.

But the region is now as volatile as it has been for a long time and Suleimani’s death has the potential to be a spark in a powder-keg. Hopefully, the fact a war is in no-one’s strategic interests overcomes urges towards revenge and national pride.