Up until last weekend, President Trump could claim a broad three-pillar policy in the Middle East: Constraining Iranian aggression, consolidating allies under the U.S. international order, and countering global terrorist organizations.

Ordering a full-scale retreat of military forces north of the Euphrates River this weekend, Trump has detonated all three pillars. The original U.S. military withdrawal from the Syrian-Turkish border area last week was deeply destructive to U.S. interests. The full retreat takes this crisis to a new level of strategic self-destruction. Let's consider each of the pillars.

Countering Iran, the Trump administration has relied on encompassing sanctions, covert action, and military deterrence. A sustaining part of this strategy has involved disrupting the Islamic Revolutionary Guard Corps as it moves capabilities from Iran into the Levant. And while Iran has been able to improve its missile threat and consolidate its influence in Lebanon, the United States has scored important successes. Iran's capabilities and confidence are considerably weaker now than they had been under the Obama administration.

Yet, Trump's retreat from northern Syria throws a grand lifeline to Iran. He has now given Iran a clear route across the Iraq-Syrian border to the Levant. America's absence means far reduced U.S. military and CIA challenge. And along with the Russians (more on them in a moment), Tehran will co-opt the YPG Kurdish militias in northern Syria. That will give Tehran greater opportunity to threaten U.S. forces redeployed to southern Syria.

Next up, U.S. allies and international order.

Again, Trump's decision jeopardizes good work. Entering office in 2017, the Trump Administration faced U.S. allies who felt betrayed by the Obama administration and increasingly threatened by Iran. Vladimir Putin used that fear to make inroads with Egypt and the Sunni-Arab monarchies under Saudi Arabia's nominal umbrella. In return for Russian military purchases and trade, Putin offered these governments his influence against Iran and his silence in face of their domestic repression. But Putin also wanted these governments to distance themselves from the U.S.

Countering Iran and offering a restored hand of friendship, Trump was able to win back these allies to America's corner. This serves long term regional stability and political reform in the service of counterterrorism.

Now, however, regimes that value perception as much as reality will perceive Trump as a most unreliable partner. These allies now have credible reason to believe Trump might abandon them on the flip of a dime. In turn, I guarantee you that Putin will be whispering as much in Mohammed bin Salman and Khalifa bin Zayed Al Nahyan's ears (indeed, Putin is visiting UAE and Saudi Arabia this week!). He'll be telling them that to trust America is to risk their future. Russia alone, he'll say, can offer their security. But, he'll add, they'll have to pony up.

Trump seems to value mercantilism above all else. So, perhaps he'll start paying notice when the monarchies decrease their U.S. arms purchases, help Russia drive up global oil prices, and assert greater domestic repression (fostering terrorist sentiments).

Finally, there's the counterterrorism concern.

Until last week, the Trump administration had waged an aggressive campaign to break ISIS apart and weaken groups like al Qaeda and the Lebanese Hezbollah. While Trump's unpredictability has caused occasional problems, he has strengthened America's regional counterterrorism cooperation. All of that is now at risk.

Most obviously, the U.S. withdrawal will allow ISIS to regroup in the heartlands of its former territorial caliphate. Absent American interdiction, ISIS fighters will move back from Iraq to retake settlements in eastern Syria's Deir ez-Zor province. Once again subjugating the moderate Sunni tribes there, ISIS will find new credibility to claim that most pernicious of Salafi-Jihadist rallying cries: "America is a paper tiger, God is with us." This will allow the group to increase recruitment and mobilize more direct action.

America's withdrawal will also force the Sunni tribes to choose between Iranian sectarianism and Bashar Assad's hordes on the one hand, and ISIS on the other. Withdrawing America's cooling influence, Trump has replicated President Barack Obama's 2011 Iraq withdrawal, and planted the ingredients for a binary sectarian conflict. A conflict in which all sides are pressured to align themselves with the extremists. ISIS and the Guards will thank Trump with genuine gratitude.

Going forwards, Trump should pay more attention in his intelligence briefings. Or he should find the courage to do that which he has done once before and change course in Syria.