This legislation aims to strengthen strategic defense cooperation between the United States and key NATO allies located on the Eastern Flank. It defines "Eastern Flank strategic defense partners" to include Bulgaria, Estonia, Finland, Hungary, Latvia, Lithuania, Poland, Romania, and Slovakia, recognizing their critical role in defending NATO's border and deterring aggression from hostile state actors. The bill establishes a U.S. policy to prioritize cooperation with these partners in implementing defense cooperation authorities and treating them as priority recipients of security assistance. Specifically, the Act directs the Secretary of State and Secretary of Defense to give priority to these partners for Foreign Military Financing , capacity building for foreign security forces, and the transfer of excess defense articles . It also prioritizes their participation in bilateral and multilateral military exercises, interoperability training, and logistics planning. Furthermore, the bill mandates prioritizing Eastern Flank partners under the War Reserve Stocks for Allies program and considering the expansion of defense article stockpiles to increase regional deterrence and reduce strategic response time. A congressional briefing on the implementation of these provisions is required within 180 days of enactment.