In the years after he was named the deputy crown prince of Saudi Arabia, in 2015, Mohammed bin Salman—known informally as M.B.S.—has accumulated remarkable power in the country. (He became crown prince in 2017.) Saudi Arabia, under his de-facto leadership, embarked on a military campaign against the Houthis in Yemen, temporarily kidnapped the Prime Minister of Lebanon, and blockaded Qatar. Many of these actions were part of a campaign to isolate Iran, whose Supreme Leader, Ayatollah Ali Khamenei, M.B.S. referred to in 2017 as “the new Hitler.” While conducting his aggressive foreign policy, M.B.S. had a close ally: Mohamed bin Zayed, the President of the United Arab Emirates. “M.B.Z. saw M.B.S. as a younger version of himself: smart, energetic, and eager to confront enemies,” Dexter Filkins reported for this magazine in 2018.

In the past few months, however, things have changed. The alliance that promised to reshape the Middle East has collapsed into acrimony, with Saudi Arabia and the U.A.E. on different sides of violent conflicts in Yemen and in Sudan. The two countries are increasingly competing for economic opportunities in the region, while Saudi Arabia sees the U.A.E. as too willing to ally with Israel, and the U.A.E. seems resentful of Saudi Arabia’s power.

I recently spoke by phone with Kristian Ulrichsen, the author of “The United Arab Emirates: Power, Politics and Policy-Making” and a fellow for the Middle East at Rice University’s Baker Institute for Public Policy. During our conversation, which has been edited for length and clarity, we discussed what’s really behind the rift in this once strong alliance, what’s driving the U.A.E.’s catastrophic intervention in Sudan, and how the Trump Administration’s transactional approach to foreign policy may exacerbate the rivalry between the two countries.

Why has a falling out occurred over the past several months?

The trigger was in early December when the U.A.E.-backed forces in Yemen, especially the separatist Southern Transitional Council, moved into two provinces of eastern Yemen and upended the fragile balance of power in Yemen. The Saudis saw this as highly provocative, as unhelpful to the anti-Houthi coalition in Yemen, and as a threat, because of the Yemeni-Saudi border, to Saudi security. And the U.A.E.’s initial advance was also on the same day Gulf leaders were meeting in Bahrain. So, in Riyadh, it was seen as a major provocation that a close ally, such as the U.A.E., would green-light an advance that was seen as so antithetical to Saudi interests.

The U.A.E. and Saudi Arabia were initially part of the same anti-Houthi alliance, as the Houthis were seen as a proxy for Iran, a regional rival for both countries. The war itself has been disastrous for Yemenis, but the thinking was that, broadly speaking, the two countries were aligned on that front.

Well, they both went into Yemen together in March, 2015. It was M.B.S.’s first major foreign-policy move after becoming minister of defense in January of that year. Initially, there was coördination between Riyadh and Abu Dhabi, especially between M.B.S. and M.B.Z., but gradually they began to diverge as Saudi forces became bogged down fighting the Houthis, while the U.A.E. was much more successful in pushing back the Houthis and reclaiming territory from Al Qaeda in the Arabian Peninsula. So the U.A.E. felt like it had accomplished its mission.

Meanwhile, the U.A.E. was coming under a lot of political pressure from the United States, and other parts of the world, about its tactics in the war. So in July, 2019, the U.A.E. announced that it was redeploying its forces, and it pulled back from the anti-Houthi battle lines in central Yemen, and switched to supporting militias and other groups on the ground, especially in southern Yemen, to insure access to a network of ports and maritime access on the Red Sea, on both sides of the Yemen-Africa coastline. Then, in 2022, a truce was reached between the Houthis and the Saudi-led coalition, which has more or less held for the past four or five years. Since then, the conflict in Yemen has been almost frozen, which made the S.T.C.’s November advance so surprising. Nobody saw it coming. And the issue of why the U.A.E. or the S.T.C. would’ve wanted to reignite the advance is probably something that the Saudis are trying to get to the bottom of. There have been reports that the U.A.E. felt that, when M.B.S. was visiting the White House in mid-November, he should not have raised the issue of the Sudanese civil war with President Trump, in which the U.A.E. has been backing a non-state militia group, the Rapid Support Forces.

I want to turn to Sudan in a minute, but it does feel that, in Yemen and across the region, Saudi Arabia has acted incredibly aggressively over the past decade. Now something seems to have switched, and the U.A.E. seems more aggressive. What changed?

Between 2015 and about 2019, you had an alignment between the U.A.E. and Saudi Arabia, between M.B.Z. and M.B.S. They were both much more interventionist and assertive, even aggressive, in their regional policies. This was after the Arab Spring. They felt that they had to be forceful in trying to push what they saw as countries that they saw supporting movements of change. Turkey and Qatar were examples. And the Saudis and Emiratis really wanted to limit radical change. And so they went into Yemen together in March, 2015. They intervened or they came together with the blockades of Qatar in 2017, orchestrating a blockade which lasted until January, 2021. And the Saudis intervened in Lebanon’s political affairs in November, 2017, holding the Lebanese Prime Minister hostage until he announced his resignation. So the Saudis were willing to intervene to project their interests across the region, and they were on the same page as the U.A.E. in many of these cases.

But what changed was the missile and drone attacks on Saudi oil infrastructure in September, 2019, which were assumed to be perpetrated by, but were never formally attributed to, Iran. And President Trump did nothing in response. He actually said, a couple of days after the attacks, “That was an attack on Saudi Arabia, and that wasn’t an attack on us.” And that sent shock waves through Riyadh and Abu Dhabi. The Saudis began to pull back immediately. They began to realize that they were perhaps on their own much more than they had thought. And so, in the twenty-twenties, they began to de-escalate tensions with Iran, improve ties with Turkey to reduce sources of geopolitical risk, and focus on internal issues and economic growth.

Meanwhile, the U.A.E. was still much more willing to take risks, including by identifying and backing sub-state networks in countries without functioning state institutions that could better support security and governance on the ground. That’s where that divergence really grew throughout the twenty-twenties.

And I assume you view Yemen as an example of this.

Yes. The Saudis feel that there has been a fragile but stable balance of power in Yemen since 2023, and that these moves by the U.A.E., or by the U.A.E.-backed S.T.C., are disruptive and unnecessary and threaten that balance of power.

You brought up M.B.S.’s visit to the White House in November, where he reportedly suggested sanctions against the U.A.E. Now we have a propaganda war on each side, with real anger from people in both governments, expressed on social media and elsewhere. I get that the two countries have different visions for the region, but does it seem like, given the speed with which this has spiralled out of control, there’s a deeper anger here?

I think this animosity is part of each side trying to insure their narrative is the one that wins out, especially vis-à-vis the Trump Administration. Clearly, what M.B.S. may or may not have said during his visit to the White House in November, and whether or not it was taken as an attack by the U.A.E., rather than just a call for sanctions on the R.S.F., is a matter of fierce debate on both sides. It could be that perceptions have been driving the respective responses to a large extent, as each side seems to believe what it wants to hear. And yes, the depth of feeling is indicative of much deeper issues at play. In Yemen especially, these splits have been increasing for years as the two countries approached the conflict in different ways, but both sides decided to ignore the ramifications of their different approaches, and now they’ve become too big to ignore.

In terms of economics and investments, the Saudis are having difficulties in attracting foreign investment. They’ve been forced to scale back on some projects. And they’re trying to move into some of the economic sectors, like travel, tourism, and entertainment, that the U.A.E. has had a twenty- to twenty-five-year head start in. So there’s increasing economic competition between the countries as well, which is part of the backdrop to this rivalry, even though, at this point, it’s more economic and security-focussed, and isn’t yet a political rupture like the one during the blockade of Qatar in 2017.

How do you think competing for the favor of the Trump Administration, which is uninterested in human rights and very interested in economic investments, changes the rivalry? There has been reporting about the U.A.E. buying huge stakes in a Trump family company.

I think Trump’s transactional approach to governing and policymaking has definitely created opportunities for the Gulf states, and both the Saudis and the Emiratis have made the most of those opportunities. In 2017, they felt that they had a once-in-a-generation chance to achieve their objectives vis-à-vis Qatar by enlisting Trump’s support. And after Trump was inaugurated in 2025, both countries reached out straight away with promises of investments, both in Trump-aligned companies and in bilateral investments. Both countries made separate pledges about investing in the U.S. economy. But they’ve done it separately. So they’re competing, I think, for the ear of the White House. Trump went to both Saudi Arabia and Abu Dhabi in May, last year. We’ve also seen the U.A.E. take the lead in A.I. over the past four or five years. In that sector, the Saudis are playing catch-up. So these things are all part of that competitive rivalry we see playing out, which now has much more of an edge to it than it did in the past.

Let’s turn to the U.A.E. specifically. We don’t know how many hundreds of thousands of people have died in Sudan, but the U.A.E.-backed R.S.F. seems to be the most brutal actor among many in this conflict. Have you been surprised by the U.A.E.’s enduring support for the R.S.F., despite the bloodshed?

I have been surprised by the fact that international criticism, even condemnation, of the R.S.F., and its pretty well-documented links to the U.A.E., including transfers of weapons under the guise of humanitarian support, hasn’t forced the U.A.E. to backtrack or to compromise its support. The U.A.E., in a way, has doubled down on the support for the R.S.F., and that, I think, has been a surprise. If you think back to Yemen in 2018, international criticism did ultimately lead to a change in approach. In Sudan, if anything has happened, it is that the atrocities committed by the R.S.F. have gotten worse. It may be that Abu Dhabi is now so entrenched and feels very defensive, even isolated in the region, that it has decided to double down on its support for the R.S.F., regardless of international criticism.

Do you view the U.A.E.’s increasingly aggressive actions in the Middle East and Africa as having some strong ideological component, or is this more about projecting regional power and securing practical ends, like port access and other business interests? Because, when we go back to the period after the Arab Spring when this approach started, there was a sense that the U.A.E. and Saudi Arabia were embarking on an ideological project that was in part about opposition to Iran, but also to a certain strain of Islamist politics, as represented by the Muslim Brotherhood in Egypt, Erdoğan in Turkey, etc.

I think there’s a bit of both. For example, the U.A.E. has intervened heavily in Libya in the past decade, in part because the Qataris were supporting what the U.A.E. views as Islamist groups in western Libya. In response, the U.A.E. intervened in eastern Libya, backing an authoritarian strongman. And, starting with that decision, you now find links between Libya and Chad and Sudan that show the networks the U.A.E. has built up in the wider regional arena.

The U.A.E. is one of the heaviest international investors in Africa. A lot of it is economic. There are heavy investments in renewable energy and infrastructure, for example, across the continent. But there is also that component of trying to push back against, as they see it, Islamist influence, by backing authoritarian strongmen who try to limit the spread of Islamist movements and groups. So there is a combination of both. And of course, in the U.A.E., Sheikh Tahnoon bin Zayed al-Nahyan is both the national-security adviser and the head of many of the country’s biggest investment groups. So you can very clearly see a link between security and investment in Emirati policy.

The Saudis were less rigid. They were more pragmatic in some ways. For example, in Yemen, the Saudis were willing to work with Islamists in southern Yemen, specifically, a group that is sort of the Yemeni offshoot of the Muslim Brotherhood, whereas the U.A.E. was adamantly opposed to working with them. Again, it goes back to risk calculations. M.B.Z. has a zero-tolerance approach to any form of political dissent. And, in that context, he believes that Islamist movements are the most likely form of political dissent. If you give them an opening, they will take more and more. And so he has a zero-tolerance approach, meant to deny them even an opening.

What do you make of the Saudis accusing the U.A.E. of becoming too close to Israel? Because, for a long time, it seemed that M.B.S. was the one hoping to get closer to Israel, and who wanted a normalization deal between the Saudis and the Israelis.

Yeah, part of the Saudi propaganda campaign has been to play up the depths of ties between the U.A.E. and Israel, and to describe the U.A.E. and Israel as being the disruptors of regional politics today. And this is even though, as you say, before October 7th, the Saudis were in dialogue with the United States over the contours of a deal with Israel. M.B.S. said it himself in a Fox News interview in late September, 2023, about three weeks before October 7th, saying that they were getting close to what would be the biggest deal since the end of the Cold War. So there was definitely a feeling that a deal was doable. Whereas now, with everything that has happened in Gaza, the price for Saudi Arabia has risen. I think they still would like to eventually normalize, but they’re going to ask for a higher price to sell it domestically.

Is Saudi Arabia more wary of domestic political pressure than the U.A.E. is?

Saudi Arabia is much larger. There are more than twenty million Saudi citizens. It’s the home of the two holiest sites in Islam. There’s a religious element to Saudi policymaking as the guarantor of Mecca and Medina. So the Saudis are always more careful about how their policies are seen, both domestically and across the Arab and Muslim worlds. So they might lack the ability of the U.A.E., which has a much smaller population, to act decisively and fast, even though M.B.S. did a lot of decisive and fast actions at the beginning of his time as crown prince. But, again, there’s more of a caution in Saudi policymaking, especially when it comes to something as sensitive as diplomatic relations with Israel, which many Saudi citizens still, in opinion polls, do not seem too enthusiastic about.

You said that M.B.S. started becoming less aggressive in 2019, after Iran’s attack on Saudi oil fields. Do you think that the worldwide condemnation of Jamal Khashoggi’s murder, in 2018, had anything to do with it, too?

It did. It certainly brought initial plans for his so-called Vision 2030 to a halt. If you remember, M.B.S. spent several weeks in the United States in 2018, meeting former Presidents, being celebrated in Silicon Valley, and meeting all the tech titans. That all came to a shuddering halt after Khashoggi’s death. M.B.S. really became persona non grata in Western circles, up until, ironically, the Russian invasion of Ukraine in 2022. Vladimir Putin’s isolation in 2022 led to the rehabilitation of M.B.S., as Western leaders realized that they had to deal with him whether they liked it or not.

Because of oil prices, you mean?

Yes, because at the time, oil prices were rising, and the West wanted Saudi support in managing oil prices and output levels. Biden, of course, went to Saudi Arabia after this and fist-bumped M.B.S., after previously having said he had to be held accountable.

A lot of the early articles about M.B.S. and M.B.Z. focussed on a kind of mentorship that M.B.Z. supposedly provided. I’m curious if you think that kind of narrative was oversimplified, and if you think their falling out has anything to do with their personal dynamic.

I’m not sure if there was ever a mentor-mentee relationship, but M.B.Z. is twenty-four years older than M.B.S., and I think M.B.Z. certainly saw in M.B.S. a version of himself, somebody who was willing to take risks (even if he’s less willing now), somebody who was willing to break eggs to make an omelette, and somebody who could see the bigger picture of economic reform. The U.A.E., like most of the other Gulf states, was concerned that with the advanced age of leadership in Saudi Arabia, and with multiple economic and social challenges building up, the Saudis needed a decisive transformation. They needed someone to really grasp the policymaking process. And in M.B.S. they found that person. Initially, M.B.Z. spent a lot of time in Western capitals talking him up. People in the West didn’t know who he was, and they weren’t sure whether to take him seriously. And M.B.Z. played a reassuring role in saying, “He’s the real deal.” So, at the beginning, he was important in establishing M.B.S.’s credibility.

I think the challenge was always that these are two headstrong characters. M.B.Z. is older, but M.B.S. is now the crown prince of Saudi Arabia, the regional leader in many ways. So I think there was always going to be a clash of character over who had the upper hand in the relationship. And we’re seeing that play out now, where neither one wants to be the one that backs down. ♦