By George Friedman

Last week, a coalition of predominantly Sunni Arab countries, primarily from the Arabian Peninsula and organized by Saudi Arabia, launched airstrikes in Yemen that have continued into this week. The airstrikes target Yemeni al-Houthis, a Shiite sect supported by Iran, and their Sunni partners, which include the majority of military forces loyal to former President Ali Abdullah Saleh. What made the strikes particularly interesting was what was lacking: U.S. aircraft. Although the United States provided intelligence and other support, it was a coalition of Arab states that launched the extended air campaign against the al-Houthis.

Three things make this important. First, it shows the United States' new regional strategy in operation. Washington is moving away from the strategy it has followed since the early 2000s — of being the prime military force in regional conflicts — and is shifting the primary burden of fighting to regional powers while playing a secondary role. Second, after years of buying advanced weaponry, the Saudis and the Gulf Cooperation Council countries are capable of carrying out a fairly sophisticated campaign, at least in Yemen. The campaign began by suppressing enemy air defenses — the al-Houthis had acquired surface-to-air missiles from the Yemeni military — and moved on to attacking al-Houthi command-and-control systems. This means that while the regional powers have long been happy to shift the burden of combat to the United States, they are also able to assume the burden if the United States refuses to engage.

Most important, the attacks on the al-Houthis shine the spotlight on a growing situation in the region: a war between the Sunnis and Shiites. In Iraq and Syria, a full-scale war is underway. A battle rages in Tikrit with the Sunni Islamic State and its allies on one side, and a complex combination of the Shiite-dominated Iraqi army, Shiite militias, Sunni Arab tribal groups and Sunni Kurdish forces on the other. In Syria, the battle is between the secular government of President Bashar al Assad — nevertheless dominated by Alawites, a Shiite sect — and Sunni groups. However, Sunnis, Druze and Christians have sided with the regime as well. It is not reasonable to refer to the Syrian opposition as a coalition because there is significant internal hostility. Indeed, there is tension not only between the Shiites and Sunnis, but also within the Shiite and Sunni groups. In Yemen, a local power struggle among warring factions has been branded and elevated into a sectarian conflict for the benefit of the regional players. It is much more complex than simply a Shiite-Sunni war. At the same time, it cannot be understood without the Sunni-Shiite component.

Iran's Strategy and the Saudis' Response

One reason this is so important is that it represents a move by Iran to gain a major sphere of influence in the Arab world. This is not a new strategy. Iran has sought greater influence on the Arabian Peninsula since the rule of the Shah. More recently, it has struggled to create a sphere of influence stretching from Iran to the Mediterranean Sea. The survival of the al Assad government in Syria and the success of a pro-Iranian government in Iraq would create that Iranian sphere of influence, given the strength of Hezbollah in Lebanon and the ability of al Assad's Syria to project its power.

For a while, it appeared that this strategy had been blocked by the near collapse of the al Assad government in 2012 and the creation of an Iraqi government that appeared to be relatively successful and was far from being an Iranian puppet. These developments, coupled with Western sanctions, placed Iran on the defensive, and the idea of an Iranian sphere of influence appeared to have become merely a dream.

However, paradoxically, the rise of the Islamic State has reinvigorated Iranian power in two ways. First, while the propaganda of the Islamic State is horrific and designed to make the group look not only terrifying, but also enormously powerful, the truth is that, although it is not weak, the Islamic State represents merely a fraction of Iraq's Sunni community, and the Sunnis are a minority in Iraq. At the same time, the propaganda has mobilized the Shiite community to resist the Islamic State, allowed Iranian advisers to effectively manage the Shiite militias in Iraq and (to some extent) the Iraqi army, and forced the United States to use its airpower in tandem with Iranian-led ground forces. Given the American strategy of blocking the Islamic State — even if doing so requires cooperation with Iran — while not putting forces on the ground, this means that as the Islamic State's underlying weakness becomes more of a factor, the default winner in Iraq will be Iran.

A somewhat similar situation exists in Syria, though with a different demographic. Iran and Russia have historically supported the al Assad government. The Iranians have been the more important supporters, particularly because they committed their ally, Hezbollah, to the battle. What once appeared to be a lost cause is now far from it. The United States was extremely hostile toward al Assad, but given the current alternatives in Syria, Washington has become at least neutral toward the Syrian government. Al Assad would undoubtedly like to have U.S. neutrality translate into a direct dialogue with Washington. Regardless of the outcome, Iran has the means to maintain its influence in Syria.

When you look at a map and think of the situation in Yemen, you get a sense of why the Saudis and Gulf Cooperation Council countries had to do something. Given what is happening along the northern border of the Arabian Peninsula, the Saudis have to calculate the possibility of an al-Houthi victory establishing a pro-Iranian, Shiite state to its south as well. The Saudis and the Gulf countries would be facing the possibility of a Shiite or Iranian encirclement. These are not the same thing, but they are linked in complex ways. Working in the Saudis' favor is the fact that the al-Houthis are not Shiite proxies like Hezbollah, and Saudi money combined with military operations designed to cut off Iranian supply lines to the al-Houthis could mitigate the threat overall. Either way, the Saudis had to act.

During the Arab Spring, one of the nearly successful attempts to topple a government occurred in Bahrain. The uprising failed primarily because Saudi Arabia intervened and imposed its will on the country. The Saudis showed themselves to be extremely sensitive to the rise of Shiite regimes with close relations with the Iranians on the Arabian Peninsula. The result was unilateral intervention and suppression. Whatever the moral issues, it is clear that the Saudis are frightened by rising Iranian and Shiite power and are willing to use their strength. That is what they have done in Yemen.

In a way, the issue is simple for the Saudis. They represent the center of gravity of the religious Sunni world. As such, they and their allies have embarked on a strategy that is strategically defensive and tactically offensive. Their goal is to block Iranian and Shiite influence, and the means they are implementing is coalition warfare that uses air power to support local forces on the ground. Unless there is a full invasion of Yemen, the Saudis are following the American strategy of the 2000s on a smaller scale.

The U.S. Stance

The American strategy is more complex. As I've written before, the United States has undertaken a strategy focused on maintaining the balance of power. This kind of approach is always messy because the goal is not to support any particular power, but to maintain a balance between multiple powers. Therefore, the United States is providing intelligence and mission planning for the Saudi coalition against the al-Houthis and their Iranian allies. In Iraq, the United States is providing support to Shiites — and by extension, their allies — by bombing Islamic State installations. In Syria, U.S. strategy is so complex that it defies clear explanation. That is the nature of refusing large-scale intervention but being committed to a balance of power. The United States can oppose Iran in one theater and support it in another. The more simplistic models of the Cold War are not relevant here.

All of this is happening at the same time that nuclear negotiations appear to be coming to some sort of closure. The United States is not really concerned about Iran's nuclear weapons. As I have said many times, we have heard since the mid-2000s that Iran was a year or two away from nuclear weapons. Each year, the fateful date was pushed back. Building deliverable nuclear weapons is difficult, and the Iranians have not even carried out a nuclear test, an essential step before a deliverable weapon is created. What was a major issue a few years ago is now part of a constellation of issues where U.S.-Iranian relations interact, support and contradict. Deal or no deal, the United States will bomb the Islamic State, which will help Iran, and support the Saudis in Yemen, which will not.

The real issue now is what it was a few years ago: Iran appears to be building a sphere of influence to the Mediterranean Sea, but this time, that sphere of influence potentially includes Yemen. That, in turn, creates a threat to the Arabian Peninsula from two directions. The Iranians are trying to place a vise around it. The Saudis must react, but the question is whether airstrikes are capable of stopping the al-Houthis. They are a relatively low-cost way to wage war, but they fail frequently. The first question is what the Saudis will do then. The second question is what the Americans will do. The current doctrine requires a balance between Iran and Saudi Arabia, with the United States tilting back and forth. Under this doctrine — and in this military reality — the United States cannot afford full-scale engagement on the ground in Iraq.

Turkey's Role

Relatively silent but absolutely vital to this tale is Turkey. It has the largest economy in the region and has the largest army, although just how good its army is can be debated. Turkey is watching chaos along its southern border, rising tension in the Caucasus, and conflict across the Black Sea. Of all these, Syria and Iraq and the potential rise of Iranian power is the most disturbing. Turkey has said little about Iran of late, but last week Ankara suddenly criticized Tehran and accused Iran of trying to dominate the region. Turkey frequently says things without doing anything, but the development is still noteworthy.

It should be remembered that Turkish President Recep Tayyip Erdogan has hoped to see Turkey as a regional leader and the leader of the Sunni world. With the Saudis taking an active role and the Turks doing little in Syria or Iraq, the moment is passing Turkey by. Such moments come and go, so history is not changed. But Turkey is still the major Sunni power and the third leg of the regional balance involving Saudi Arabia and Iran.

The evolution of Turkey would be the critical step in the emergence of a regional balance of power, in which local powers, not the United Kingdom or the United States, determine the outcome. The American role, like the British role before it, would not be directly waging war in the region but providing aid designed to stabilize the balance of power. That can be seen in Yemen or Iraq. It is extremely complex and not suited for simplistic or ideological analysis. But it is here, it is unfolding and it will represent the next generation of Middle Eastern dynamics. And if the Iranians put aside their theoretical nuclear weapons and focus on this, that will draw in the Turks and round out the balance of power.