For five years, President Obama has more or less successfully adhered to a very specific, though not immediately discernible, doctrine when formulating American policy in the Muslim world.

Many foreign policy experts believe that Obama doesn’t have a Middle East policy at all ― a clear-cut set of ideas that guide American engagement in the greater Middle East. This, we are told, is a big problem.

But the conventional wisdom is wrong. There is, in fact, an Obama doctrine. And for the first time since becoming president, Obama seems poised to violate it in an irredeemable way.

First things first: the doctrine. I call it the Doctrine of Disentanglement. Barack Obama is President of the United States because his predecessor invaded one too many Muslim countries. Bush’s presidency might today be considered a success had he limited himself to the war in Afghanistan. But he is widely thought to have overreached in Iraq, and his presidency foundered, clearing a path for an Illinois politician who, as an unknown state senator, denounced not all wars, just stupid ones.

The crucial first lesson of the Bush presidency for Obama was simple: Disentangle the U.S. from Iraq, and then Afghanistan. He has pursued this policy of disentanglement with great vigor, even in the face of obvious evidence that U.S. withdrawal from these nations could well have consequences that will one day force America to re-engage. Short-term, and particularly domestically, these policies have been successful.

The second prong of the Doctrine of Disentanglement is to avoid new entanglements.

Obama was tempted to try to make peace between Israelis and Palestinians, but quickly thought better of it (the peace process now taking place in fits and starts is the secretary of state John Kerry’s idea, and largely John Kerry’s problem, should it fail.) Obama participated (from behind, of course) in the liberation of Libya only because it seemed at the time like a clean mission, but, again, he soon learned better: He did not receive the thanks of a grateful America for helping to defeat Muammar Gadhafi, and he suffered personally and politically because of the subsequent attack on the American mission in Benghazi.

There are many legitimate criticisms of the largely passive role Obama played in the various dramas of the Arab Spring ― again, a passivity born of an almost pathological desire to keep away from complicated Middle Eastern messes ― but two things can be said in his general defense. The first is that he has operated from an often appropriate understanding of the limitations of American influence in Arab societies that are undergoing traumatic upheavals (contrast this restrained approach with the remake-the-world philosophy ― one I used to share ― of the liberal interventionists and neoconservatives).

The second is that he has largely succeeded in protecting American life and property during an extended period of disastrous volatility.

Yes, there is a price to be paid for passivity: One is the now-fixed perception among American allies, including Saudi Arabia, Israel, the United Arab Emirates and Jordan, that Obama either doesn’t care about them (meaning, in other words, that he is unable to discern his country’s obvious interests in the Middle East) or is simply too irresolute to protect them through the projection of American power.

This fear manifests itself in the anxiety these allies feel about Obama’s willingness to confront the Iranian nuclear program, and about Obama’s readiness, more broadly, to confront the threats posed by Iran and its allies, the Assad regime and Hezbollah, as well as their friends in Moscow.

Which brings us to the current moment, which threatens to undo once and for all the Doctrine of Disentanglement.

America is poised to strike at the Assad regime in good part because Obama could not resist the urge, last year, to declare publicly the existence of a chemical weapons red line that the Assad regime should not cross. Obama could not resist because the urge was morally irresistible. Like any decent human being, and like anyone with respect for international law and international norms of behavior, Obama was repulsed by the idea that the Assad regime would deploy poison gas against his own people, and he said so.

Obama, by demarcating a red line, placed American credibility on the line. If the world is to maintain the taboo against the use of chemical weapons, then the world’s superpower, which does so much to ensure global stability, must act, particularly when its leader has previously threatened to act.

But how to act? The Obama Administration appears to have an answer: Missile strikes of limited duration, meant to reinforce the taboo against the deployment of poison gas, but not to threaten the existence of Syrian regime, because “regime change,” of course, is one of those terrible, entangling, Bush-era ideas.

But the only way to ensure that Assad does not again use chemical weapons is to remove him from power. The only way to make the point that, in the post-Holocaust world, it is profoundly unacceptable to use poison gas on human beings, is to help remove the regime that violated the taboo.

If Obama strikes at Syria in a limited fashion, he will still be violating his own core doctrine, but for limited payout. He will simply be signaling to Assad that it is permissible to kill civilians with guns and bombs, but not with gas. If Assad survives an American onslaught, he might very well judge the U.S. a spent force, and continue using gas anyway.

This is why the Obama plan for Syria, as we currently understand it, is inadequate to the challenge. It is better to risk full-scale entanglement, and devise a long-term plan to help the Syrian opposition overthrow the regime, than to fire missiles at a handful of regime targets while leaving the regime itself intact.

This may be one of the toughest moments President Obama has faced in five years: the moment when the behavior of evil men finally forces him to truly engage with the catastrophic Middle East.

By Jeffrey Goldberg

Jeffrey Goldberg is a Bloomberg View columnist. He is the author of “Prisoners: A Story of Friendship and Terror.” ― Ed.

(Bloomberg)