Will Trump once again fall for a Saudi charm offensive? Let's hope not. We need to resist the spell of the Saudi royals. The U.S.-Saudi relationship is increasingly conflicted, and mutual expectations are unlikely to be met.

Aaron David Miller and Richard Sokolsky | Opinion contributors

Prince Mohammed bin Salman, the young man who will likely be the next king of Saudi Arabia for a good half century or more, is in Washington this week for his third meeting with President Trump. Not since Franklin D. Roosevelt met Abdul Aziz ibn Saud, the founder of the modern Saudi state in 1945, has an American president seemed so smitten with Saudi royalty.

We should welcome the reforms that MBS (as he's known) promises for Saudi society, particularly if they lead to changes in a virulent strain of Islam, and his desire for Saudi Arabia to become more self-reliant abroad. But we need to avoid falling under the spell of a future king whose assertive policies don't always align with our own.

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MBS’ efforts to remove obstacles in his path to power, including his recent campaign to arrest hundreds of rich Saudis, reveal that he’s got a much deeper authoritarian streak than his predecessors. He has also likely made promises he cannot keep on Israeli-Palestinian peacemaking and has already dragged the U.S. into his misbegotten regional schemes and misadventures.

The beaming smiles and bonhomie of this visit cannot hide a much deeper problem in the relationship. The oil-for-security bargain that was long the glue that cemented the U.S.-Saudi relationship has come unstuck, leading the two nations to pursue conflicting interests.

Trump’s fascination with the Saudis has been driven by personal, policy and business considerations. Saudi Arabia was his first stop on his first trip abroad, and he was feted and flattered in a blatantly transparent plan to suck up to him. He was accompanied by dozens of important CEOs from U.S. companies; business and arms deals were signed, and the message was delivered that the U.S.-Saudi tensions of the Obama era were in the past. There was no mention of the Saudis' human rights abuses, inhumane bombing of Yemen, and export of one of the most intolerant strains of Islam.

The other piece of presidential business was to seal Saudi support for Trump’s efforts to reach “the ultimate deal” between Israelis and Palestinians. The president’s son-in-law Jared Kushner has been given the lead role and had already established a relationship with MBS. But in the past several months, partly as a result of the president’s decision to recognize Jerusalem as the capital of Israel and open an embassy there, the Saudis seem to be pulling back.

Trump is banking heavily on Saudi financial carrots and sticks to pressure the Palestinians to accept the U.S. plan, and the promise of direct contacts to attract the Israelis. But it's a real stretch to think the Saudis will deliver without the Israelis and the U.S. doing far more for the Palestinians, and that's likely to create tensions between Trump and the Saudis.

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Abroad, MBS has been reckless. He has taken Iran bashing to an incendiary new level by hinting at Saudi interest in toppling the regime in Tehran — a view that appears to be shared by Trump, Secretary of State nominee Mike Pompeo, and United Nations Ambassador Nikki Haley. He has escalated the Saudi crusade to keep Iran in a box, in part to boost his legitimacy and credibility at home.

Saudi efforts over the past year to defeat the Houthi Zaydi rebels in Yemen, in a pointless military operation that has caused untold human suffering, are meant to contain Iran and get Tehran to stop meddling in the Saudis' backyard. This all reflects a dangerous obsession with Iran and a more militant strategy to roll back Iranian influence. The Saudi machinations have not only worsened the problems they were intended to solve in Qatar and Yemen, they have also handed Iran, al-Qaeda and the Islamic State new opportunities to expand their influence.

The Saudi posture toward Iran has obvious appeal to the Trump administration. However, chest-thumping U.S. rhetoric toward Iran has not yet been backed by military action, a source of Saudi frustration and disappointment. And beyond the rhetoric the administration has no viable strategy for toppling the Iranian government or crippling Iran’s regional influence by removing Syrian president Bashar Assad.

The Trump administration may also disappoint the Saudis if it walks away from the nuclear deal with Iran. There was a time when the kingdom wanted to kill it as badly as the president, but the Saudis now seem to understand that Iran will present much more of a challenge if it is not constrained by the nuclear agreement.

As king, MBS will likely preside over a changing U.S.-Saudi relationship. The U.S. is less dependent on Arab hydrocarbons; indeed, as result of skyrocketing shale oil production, the U.S. is now a major competitor with the Saudis in the global oil market. The administration’s aversion to using military force to roll back Iranian influence has sown Saudi doubts about U.S. security commitments. As a consequence, Riyadh is hedging its bets by deepening relationships with Russia and China to acquire weapons, attract investment, and cut deals on oil and nuclear power.

The U.S.-Saudi relationship is based on mutual expectations that are unlikely to be met. It will endure but it’s likely to remain far more fraught and complex and, in the years ahead, increasingly less beneficial for the United States.

Aaron David Miller, a vice president at the Woodrow Wilson International Center for Scholars and a former State Department adviser and Middle East negotiator, is the author of The End of Greatness: Why America Can’t Have (and Doesn’t Want) Another Great President. Follow him on Twitter: @aarondmiller2. Richard Sokolsky, a senior fellow at the Carnegie Endowment for International Peace, served in the State Department for 37 years.