What would Iran’s leaders really fear? Above all, a revival of the Green Movement that nearly toppled the regime following the stolen presidential election of 2009. As Omid Memarian of the Center for Human Rights in Iran noted recently in Foreign Affairs, “The ferocity with which the authorities have persecuted human rights lawyers, who bring abuses to both domestic and international attention, reflects their fear of exposure and their urgent desire to evade accountability.”

Unfortunately, the task of helping to revive the Green Movement — ideally, by providing the type of public and covert support the Reagan administration once gave Solidarity in Poland — has been made harder by Trump’s general indifference to human-rights issues, to say nothing of his rhetoric and policy toward migrants. Who knew that abandoning American values would have strategic repercussions?

A third implication is that we may be witnessing the beginning of the end of the American era in the Middle East. Trump has boasted of his willingness to support the House of Saud (not least when it’s butchering journalists) and even seemed to be asking for Saudi direction when it came to responding to Saturday’s attacks.

At the same time, Trump has also made plain his desire to withdraw from Syria and Afghanistan (to Iran’s advantage in both cases), his reluctance to re-establish deterrence with Tehran through a limited military reprisal, and his general skepticism regarding America’s role in policing the global commons. That ought to be music to the ears of America’s quasi-isolationists, including Trump’s critics on the left.

But it ought to frighten America’s traditional Mideast allies. It’s long been obvious that Saudi Arabia can’t defend itself despite its $68 billion military budget — and that’s probably just as well. If the U.S won’t defend it, who will? If it’s undefended, what might Iran do next? It’s worth remembering that there is a large and unhappy Shiite minority in eastern Saudi Arabia.

Those who don’t like Saudi Arabia as it is will like it even less when it’s gone.

That’s a thought that ought to be at the top of Robert O’Brien’s mind as he assumes the role of Trump’s national security adviser — with the tremulous optimism of a new bride joining Henry VIII at the altar. How the U.S. responds to an unprovoked attack on one of the central pillars of the global economy is a test of American leadership. The consequences of failure will be felt for years.

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