In  yet another surprising tactical maneuver, Russian President Vladimir Putin announced on Monday, March 14, that he is withdrawing the main part of his forces from Syria. While it may be premature to assess both the motive and final level of the drawdown, this could be a potential pivot in this seemingly endless crisis.

Moscow is probably feeling relatively confident in Syrian President Bashar al-Assad’s position and the overall direction of the peace talks and is also increasingly concerned about the high cost of the operation — during a period of a weak ruble and very low oil prices, upon which the Russian economy is dependent.

The interesting question is whether this retreat provides an opening for a significant Arab ground force to be inserted into the conflict. Coincidentally, just as Russia is pulling forces out of Syria, Saudi Arabia is completing a significant military exercise that may prove to have been a dress rehearsal for Sunni Arab engagement on the ground in that conflict. Indeed, just last week in the deserts of Saudi Arabia, some 350,000 troops, 20,000 tanks, dozens of ships, and 2,500 warplanes from 20 countries concluded the largest military exercises ever held in the Middle East.

Dubbed “North Thunder” (Raad al-Shamal in Arabic), these huge, historic ground, air, and naval exercises have been called war games. But make no mistake: They are anything but games. This is an effort described by Saudi Arabia and its allies to create a cohesive force to combat terrorist organizations such as the Islamic State, al Qaeda, al-Shabab, and perhaps even Boko Haram — as well as to send a strong signal to Iran, a country exhibiting expansionist ambitions to say the least.

The exercises emphasized training conventional forces to conduct low-intensity combat operations against nonstate armed groups. Another stated goal is improving the inter-operability of the armed forces of Saudi Arabia and its allies so that they can coordinate their maneuvers in spite of differing languages, military equipment, and operating systems. It also included maritime and bombing exercises designed to project power over distance. While the three weeks of war games concluded on March 10, the hope is that their impact will be long-lasting and far-reaching. The real question, of course, is whether this massive exercise is only a show of force or whether it portends the actual deployment of combat power to troubled spots in the region.

The war in Yemen continues to grind along after nearly a year of medium-level combat. Saudi forces have led the effort against the Houthi rebels who overthrew the government there, and part of North Thunder was training for the special forces and heavy ground units that will be essential going forward if the conflict cannot be resolved through negotiations. While there areflickers of diplomacy about the possibility of direct talks between the rebels and the Saudis, the North Thunder exercise is clearly designed to demonstrate the capability of the kingdom to the Iranians who back the Houthis.

The principal theater of conflict in the region is, of course, Syria. The Saudis have spoken publicly about their willingness to put boots on the ground in support of the moderate Syrian forces fighting Assad, and it is possible to see North Thunder as a training and motivating event to build a Sunni Arab coalition to do so. Whether that actually occurs will depend on the Syria negotiations led by the United States and Russia, but particularly in a partition or federalization scenario, an Arab ground force could be an important guarantor of security in the Sunni part of Syria.

For many years, the United States has been urging predominantly Muslim countries to take a stand against violent extremism.

Spurred by its hard-driving defense minister, Deputy Crown Prince Mohammad bin Salman, Saudi Arabia isstepping up to the challenges of mobilizing the mostly Muslim nations of the Middle East, South Asia, and North Africa for their common defense. The 30-year-old minister is also a catalyst for dramatic economic reforms that he hopes will strengthen Saudi Arabia’s security role. And as an American ally for at least seven decades, Saudi Arabia has long been a leader in the Gulf Cooperation Council and its Peninsula Shield force, together with Kuwait, the United Arab Emirates, Qatar, Bahrain, and Oman.

Now, Saudi Arabia is broadening its geostrategic horizons. In December, the kingdom announced a new coalition of 34 majority Muslim countries from Africa and the wider Middle East to counter violent extremism not only on the battlefields but also in the battle of ideas. The recent military exercises brought together military units from many members of this coalition, including not only the Gulf states but also Egypt, Jordan, Pakistan, Sudan, Malaysia, Morocco, and Tunisia. And as part of its strategic relationship with Ankara, Saudi Arabia has sent fighter jets to the Incirlik Air Base in southern Turkey to expand its role in the U.S.-led air campaign against the Islamic State.

As these actions underscore, Saudi Arabia and its allies appear to be assuming greater responsibility for regional and international security, stepping into what many consider to be the leadership vacuum left by American retrenchment in the Middle East. All of these countries are responding to multiple security threats. Violent extremists are occupying large swaths of territory in Syria, Iraq, and Libya. Meanwhile, enriched and emboldened by the lifting of sanctions through the recent nuclear agreement with the United States and its Western allies, Iran is meddling in Lebanon, Syria, Yemen, Iraq, and even other Gulf states. Consequently, predominantly Sunni countries such as Saudi Arabia and its allies fear the emergence of Iran as a regional hegemon, assuming leadership over the Shiites in the Middle East and seeking to destabilize majority Sunni societies. This is a geopolitical showdown between Tehran and Riyadh, overlayed with the Sunni-Shiite religious conflict; the potential turbulence may go on for decades.

It seems quite clear that Saudi Arabia and its allies are sending the United States a message: “We are still willing to trust you and work with you. But at the same time, we are ready, willing, and able to go it alone, if need be.” America and its Western allies should seek to reinforce, not reduce, their strategic partnership with Saudi Arabia. If Riyadh and its allies are left to act alone, amid increasing instability and insecurity, the already volatile Middle East may become even more unsettled and the war on terror could be undermined.

Over time, the United States should be encouraging connections between this nascent Saudi-led coalition and its two significant allies operating in the region — Israel, which represents the strongest partner to the United States in the Levant; and NATO, which has demonstrated its willingness to participate in operations defending Western interests in Libya, Iraq, and Turkey. Connecting Sunni leaders with Israel and NATO could be a powerful next move for the United States in the region — albeit a difficult one.

The presence of Saudi and other Sunni troops in Syria is a mixed blessing. It would strengthen the moderate Sunni resistance significantly, weaken Assad’s regime, increase U.S. intelligence gathering immeasurably, and create in effect a large safe zone — if coupled with U.S. air power. But it would also exacerbate the uber-conflict in the region between the Kingdom of Saudi Arabia and the Islamic Republic of Iran. On balance, the benefits to the people of Syria would probably outweigh the larger geopolitical risk but barely. And it would require a great deal of U.S. attention and engagement to manage the anti-Assad and counter-Islamic State coalition.