Donald Trump made one of the biggest mistakes of his presidency in the spring of 2017, when he offered an unconditional embrace to the then-emerging 31-year-old ruler of Saudi Arabia, Mohammed bin Salman, and adopted his agenda of aggressively confronting Iran. Three years later, as Trump grapples with the greatest crisis he has faced, that choice is costing him dearly.

Trump’s slow and stumbling response to the novel coronavirus pandemic helped accelerate last week’s stock market dive and mounting public uncertainty. But the trouble in the markets was also turbocharged by the latest reckless moves by the Saudi crown prince. Against the advice of his own ministers, Mohammed bin Salman, known as MBS, moved to flood markets with cheap Saudi oil, causing the global price to plunge and endangering the U.S. oil industry.

That, no doubt, prompted the phone call Trump made to MBS last Monday, as stocks were plunging. It’s an easy guess that the president’s message resembled the public statement of his Energy Department, which decried “attempts by state actors to manipulate and shock oil markets.”

Yet MBS’s reaction was to thumb his nose at the U.S. president. On Wednesday, his oil minister announced another big increase in petroleum production. U.S. stocks swooned again.

Then came the rocket attack by an Iranian-backed militia on a base in Iraq, which killed two U.S. servicemen. That set off a tit-for-tat cycle of U.S. airstrikes and new rocket attacks that has brought Trump back to the brink of war with Iran — a resumption, at the worst possible moment, of an entirely unnecessary conflict that he embarked upon at the behest of MBS and Israeli Prime Minister Benjamin Netanyahu.

Since making Riyadh the site of his first foreign trip as president, Trump has stubbornly defended the Saudi ruler through multiple misadventures, from the disastrous war in Yemen and failed boycott of neighboring Qatar to the murder of U.S.-based journalist Jamal Khashoggi. The big Saudi purchases of U.S. weapons that MBS promised Trump have not materialized. Instead, the president’s reward is to be stiffed by his supposed ally at his moment of greatest need, with U.S. markets whipsawing and U.S. soldiers dying.

The Saudis claim that MBS is not intentionally seeking to sabotage Trump. The crown prince’s real quarrel, they say, is with Russia’s Vladi­mir Putin, who refused to go along with a Saudi proposal to cut oil production to stabilize prices, thus prompting MBS to rashly pump more while cutting prices.

Yet, in doing so, the crown prince is merely abetting a prime Putin aim, which is to drive the fragile U.S. fracking industry out of business. Not surprisingly, the Russians reacted calmly to MBS’s dumping gambit, saying they could live with rock-bottom oil prices for six to 10 years. U.S. frackers can’t — nor, for that matter, can MBS, who has already strained the kingdom’s finances to the breaking point.

One of the most consistent themes of Trumpian rhetoric has been the ways in which U.S. allies have supposedly exploited Washington’s weakness to pursue their own interests at America’s expense. In one of his first ventures into foreign policy, Trump bought an ad in the New York Times in 1987 to make that case against, among others, Saudi Arabia, “a country whose very existence is in the hands of the United States.” He wrote: “The world is laughing at America’s politicians as we protect ships we don’t own, carrying oil we don’t need, destined for allies who won’t help.”

Saudi Arabia still depends on the United States for its survival. U.S. warships are still protecting tankers carrying Saudi oil in the Persian Gulf, even though the United States needs imported petroleum far less than it did in 1987. What’s more, Trump has dispatched thousands of U.S. troops to the kingdom to defend oil fields from Iranian attack, escalating tensions that have now led to multiple U.S. deaths and injuries.

And yet, Trump has been curiously passive as MBS has repeatedly worked against U.S. interests. Consider the case of Saud al-Qahtani, the close aide to the crown prince who is believed to have overseen the murder of Khashoggi and a hacking campaign targeting MBS’s foreign critics. Senior U.S. officials have repeatedly pushed MBS to hold Qahtani accountable, or at least sideline him; yet as Ben Hubbard of the New York Times reports, “he is still commanding armies of bots and overseeing the kingdom’s electronic spying operations.”

Or consider Trump, with his reelection prospects in danger of crumbling along with the U.S. economy, asking the crown prince to act in his own, as well as the U.S., interest and stop pushing down oil prices amid a market panic — and then remaining silent as a dictator he has coddled for three years does the opposite. Surely, Vladi­mir Putin is laughing.

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