In almost two centuries, the U.S. military has not fought a war alone. The next war will likely be no different. While we must be capable of fighting and winning on our own, we are stronger and more formidable when we can rely on partner nations and allies to stage, support, maneuver, and execute the fight together.In the sustainment community, we must set the conditions now to maximize interoperability and minimize coordination delays at the time of need. Three key efforts we must focus on include power projection, prepositioned stocks, and partner capacity.Allies and partners enable strategic readiness--the Army's ability to mobilize, deploy, and sustain forces in large-scale combat operations. Our installations and power projection platforms, which allow our military to train and move to the fight--across land, sea, and air--do not exist solely on U.S. soil. We rely on partner nations for use of terrain, ports, rail, roads, airfields, and critical infrastructure that receives, stages, and speeds troops to the frontlines. Multinational exercises, such as Pacific Pathways and DEFENDER-Europe 20, allow logisticians to train side-by-side with our allies and develop the essential tasks necessary for joint security, staging, reception, and onward movement operations. We must continue to exercise the ability to stage together, move together, and fight together.Our intention will always be to deter war and aggression, and Theater Stocks and Army Prepositioned Stocks (APS) serve as key strategic deterrents. For the past two years, we have focused on combat configuration by adding enablers such as communications equipment and weapon systems to ensure prepositioned equipment is ready to draw and quickly move to the fight. We are also reviewing all APS sites to ensure equipment sets are located, sized, and configured to best meet theater requirements. However, make no mistake; our ability to maintain healthy, robust prepositioned stocks requires the support of partner nations. Through, and in support of, combatant commands (CCMD) and Army Service Component Commands (ASCC), we must continue to cultivate the critical relationships that allow us to strategically locate, store, project, and maintain APS.The strength of our allies directly correlates to the overall strength of the coalition force. We build partner capacity and strength through programs such as Foreign Military Sales and Security Assistance Training. FMS fosters long-term relationships with allies and partner nations, providing access to the "total package" of material, spare parts, publications, technical documentation, maintenance support, and other services. Meanwhile, we leverage Security Assistance Training teams to train and advise partner armies, bolstering complementary capabilities and interoperability that will serve us well on the battlefield.Strengthening alliances and attracting new partners is key to the strategic approach in the National Defense Strategy, and Army leaders have consistently reinforced allies and partners as a priority. From increased interoperability on the battlefield to partner agreements that enable freedom of movement and maneuver, our allies and partners will be critical to deter war, and, if necessary, fight and win war. The sustainment enterprise must remain in close coordination with, but more importantly in support of CCMDs and ASCCs to foster these critical relationships.--------------------Gen. Gustave "Gus" Perna is the commander of Army Materiel Command at Redstone Arsenal, Alabama.--------------------This article was published in the January-March 2020 issue of Army Sustainment.