A meaningful review of U.S. force posture in the Middle East is long overdue.

We explored why in the first article in our series for Defense One, noting challenges with Iran, competition with Russia and China, counterterrorism imperatives, and domestic political and budgetary realities. This assessment has only been reinforced by the subsequent release of the Trump Administration’s National Defense Strategy, or NDS, with its focus on strategic competition with China and Russia, as well as the administration’s hard-line approach to Iran.

In our second article, we examined a range of Middle East scenarios and identified four factors to consider when reshaping regional force posture. Now, we offer some recommendations about gradually changing that posture to reflect evolving priorities and challenges.

To be clear, the U.S. military will never leave the Middle East. We are not advocating that it do so. However, if Defense Secretary Mattis wants to fulfill the NDS mandate to focus on China and Russia, the U.S. military’s posture in the Middle East must get smaller and smarter.

First, the United States must increase the emphasis of non-military tools, which will be vital to enabling regional partners to address long-term challenges of governance, fraying of social contracts, and consolidating counter terrorism and territorial gains into stabilization. Such initiatives will require sustained and accountable funding from both the Department of State and USAID, whose budgets have been slashed in the first two years of the Trump Administration. In addition, the United States has yet to appoint as many as half of its ambassadors to the region. While career foreign, civil, and military service officers can carry forward initiatives quite capably, the absence of the President’s representatives in key partner countries limits the political effectiveness of the United States at a time when geopolitical competitors such as Russia and China are deepening their relationships in the region – and ability to broker the posture adjustments we recommend in this article. To this point, the administration must look beyond one commonly used tool — U.S. arms sales — to compete with growing Russian influence in the Middle East; it must strengthen other U.S. diplomatic, economic, intelligence and strategic communication tools that will be critical to enabling a competitive strategy in the region.

Second, the United States should gradually reshape its “furniture” in the region — that is, its military bases, assets, and military personnel in the Middle East. This may involve reductions but with an emphasis on smart investments. The goal should be to leave enough for ongoing operations and likely potential contingencies, yet assume some risk in less likely scenarios as prescribed by the NDS, which calls for “calculated risk-taking” five times in its unclassified summary. For example, CENTCOM could relax its requirements for a continuously present carrier strike group. Ground forces and strike assets could also be drawn down somewhat. Finally, the proliferation and growth of service and unified command headquarters in the Gulf region should be rolled back through delayering and reducing staff numbers. This last issue will also strengthen U.S. civilian actors in the region by minimizing the viceroy dynamic that has gained steam over the last two decades.

What U.S. forces should remain to deter Iran, counter terrorism, secure access to strategic waterways, and support allies and partners? Important elements include:

Ballistic missile defense.

Adaptable naval and marine configurations that provide littoral, amphibious, lift, strike, maritime domain awareness, and maritime security capabilities.

Special operations and counter terrorism capabilities.

Intelligence, surveillance, and reconnaissance capabilities.

Logistics and enablers required to perform these functions.

Third, the United States should streamline its military bases in the region. Research by the RAND Corporation has upended a core assumption of the role of bases in securing access for contingencies; a 2014 study found that “the presence of large permanent bases does not increase the likelihood of securing contingency access.” The array of U.S. bases, primarily situated in the Gulf, that have been sustained and built upon since the 1991 Gulf War, were critical to conducting successive wars in Iraq and remain so for operations in Afghanistan and efforts to fight terrorism and deter Iran. While the latter three missions will remain key features of the U.S. regional approach across a range of possible scenarios, conducting these operations and preparing for the possible crises and contingencies that may emanate from future conflicts do not necessitate keeping all of its current bases “hot” in the region. “Hot” bases are continuously manned, operated, and maintained by the primary force user – in this case the United States – and the host nation. Instead, the United States could shift some of its bases from “hot” to “warm,” primarily operated and maintained by the host country under an agreement that permits U.S. forces to surge there when needed.

The criteria for determining which bases should be hot and warm could be based upon the type of capabilities needed in certain parts of the region, where strong security-cooperation relationships already exist to burden-share capabilities, and calculations of where the United States could assume some risk. One example to consider is Kuwait, where the U.S. military’s long and deep relationship could allow for a transition to warm bases and where a heavy ground-based posture is less relevant for the region’s challenges. Such transitions could be offset by further security cooperation investments to assure critical Gulf partners of U.S. commitment.

Fourth, the United States will need to design a series of mitigation measures to absorb any risks of adjusting its current force posture. These steps should include increasing prepositioned equipment stocks in the region and deepening security partnerships through tailored and targeted advising, institution building, training, exercises, exchanges, and equipping to enable partners to address common security objectives. Exercises with a number of regional militaries, for example, are useful both strategically—deterring Iran, reassuring Gulf partners, and facilitating cooperation among them given frayed political relationships—and operationally in ensuring the U.S. military maintains readiness for future Middle East conflicts, particularly as it focuses increasingly on other regions. Working with allies such as the United Kingdom and France to pool resources, basing, and synchronizing carrier deployments as allied capabilities and regional bases come on line would also help offset changes in U.S. posture. Harnessing opporutnities to share resources across U.S. combatant commands also provides efficiencies; CENTCOM already shares ISR resources with AFRICOM. Future sharing with EUCOM, AFRICOM, and INDOPACOM could include maritime and strike capabilities. And while we have focused on posture adjustments, undoubtedly there are changes that could be made in force development, too, such as investments in security force assistance brigades and light attack aircraft.

We do not recommend these adjustments lightly, as threats and challenges persist in the Middle East region. The administration’s decision to withdraw the United States from the Joint Comprehensive Plan of Action to curb Iran’s nuclear program and seek a more assertive approach to address Iran’s destabilizing behavior may trigger escalations that the United States will need to be prepared to address—in close coordination with allies and partners. However, changing realities of the security environment and U.S. political and budgetary dynamics have prompted deep introspection in the Defense Department. It’s time to make gradual adjustments in the CENTCOM theater to reflect it.

Congress should task the Pentagon to consider how to reshape its posture, reporting back through both classified and unclassified, publicly available assessments. These assessments should include an explanation of how DoD plans to apply its global operating model and dynamic force employment concepts outlined in the NDS in the Middle East context and how war plans will necessarily also change with posture adjustments. The region will continue to pose considerable and evolving challenges to U.S. national security. U.S. policymakers should aim to shape U.S. posture to be flexible, adaptive, and responsive to meet requirements in the CENTCOM theater but also in the context of global priorities.