On January 19, 2018, Secretary of Defense Mattis released the unclassified summary of the Department of Defense's (DOD) first congressionally mandated National Defense Strategy (NDS). In addition to stating DOD's approach to contending with current and emerging national security challenges, the NDS is also intended to articulate the overall strategic rationale for programs and priorities contained within the FY2019-FY2023 budget requests. Overall, the document maintains that the strategic environment in which the United States must operate is one characterized by the erosion of the rules-based international order, which has produced a degree of strategic complexity and volatility not seen "in recent memory" (p. 1). As a result, the document argues, the United States must bolster its competitive military advantage—which the NDS sees as having eroded in recent decades—relative to the threats posed by China and Russia. It further maintains that "inter-state strategic competition, not terrorism, is now the primary concern in U.S. national security." (p. 1)

Statutory Requirement

Particularly since the end of the Cold War, the Pentagon has regularly reviewed its strategy, policy, and programs to ensure they are appropriate to the current and emerging strategic landscape. Over time, these reviews became congressionally mandated and referred to as the "Quadrennial Defense Review." Eventually, dissatisfaction with the QDR process and its associated outcomes led Congress to rewrite the requirements for these DOD strategy documents. The FY2017 NDAA, P.L. 114-328, Section 941, amended Title 10, United States Code, Section 113, to require the Secretary of Defense to produce an NDS which articulates how the Department of Defense will advance U.S. objectives articulated in the National Security Strategy, released in December 2017. The document released on January 19^th represents a summary of the full NDS, which is itself classified.

What the NDS Says

Consistent with comparable documents issued by prior administrations, the NDS maintains that there are five central external threats to U.S. interests: China, Russia, North Korea, Iran, and terrorist groups with global reach. The NDS mandate requires DOD to prioritize those threats. Accordingly, retaining the U.S. strategic competitive edge relative to China and Russia is viewed a higher priority than countering violent extremist organizations. Further, the NDS appears conceptually consistent with the National Security Strategy regarding the notion that "peace through strength," or improving the capability and lethality of the joint force in order to deter warfare, is essential to countering these threats. It also contends that, unlike most of the period since the end of the Cold War, the joint force must now operate in contested domains where freedom of access and maneuver is no longer assured.

As such, it organizes DOD activities along three central "lines of effort"—rebuilding military readiness and improving the joint forces' lethality, strengthening alliances and attracting new partners, and reforming the department's business practices—and argues that all three are interconnected and critical to enabling DOD to effectively advance U.S. objectives. It also notes that programs designed to advance those objectives will be included in the FY2019-FY2023 budgets. Some further key points include

• Building a more lethal joint force will require consistent multiyear investments to improve war fighting readiness, an optimally sized joint force, prioritization of preparedness for war as part of an overall deterrent and competitive posture, and the modernization of key capabilities. The latter includes nuclear forces; space and cyberspace capabilities; command, control communications, computers and intelligence, surveillance and reconnaissance (C4ISR) capabilities; missile defense; joint lethality in contested environments; forward maneuver and posture resilience; autonomous and unmanned systems; and resilient logistics (p. 6-7).
• Strengthening allies and attracting new partners will require better burden-sharing amongst allies; expanding regional consultative mechanisms and collaborative planning; and deepening interoperability amongst allies and partners (p. 8-9).
• Reforming DOD for greater performance and affordability will require prioritizing speed of capability delivery rather than the "exquisite" performance of systems and capabilities; better organizing the Department to enable innovation to improve lethality across the joint force; better budget discipline and affordability; rapid prototyping and fielding of equipment; and harnessing and protecting the National Security Innovation Base (p 10-11). The NDS sees harnessing that base as a source of competitive advantage

Potential Questions for Congress

As Congress considers the NDS, as well as the programmatic and resource decisions to be proposed by the Trump Administration to accomplish objectives contained within the strategy, it could consider the following points:

• What is the force sizing construct? The central conceptual underpinning of the NDS—and all defense strategy reviews prior to it since the end of the Cold War—is the "force sizing construct" (FSC). The FSC is, essentially, a heuristic that allows planners to judge whether the size and composition of the military is sufficient to meet the national security challenges facing the United States. What are the assumptions that went into this FSC? Is the FSC an appropriate guide for building a joint force that can meet the national security challenges the U.S. faces? How flexible is the construct over multiple possible crises?
• What is the appropriate balance of investment between force size and capability modernization? Secretary Mattis appears to prioritize capability modernization. Yet concerns about force overstretch due to high operations tempos over the past 15 years have prompted some observers to note that investments in additional forces may be necessary, especially given that contending with any one of the 5 key national security challenges in the NDS might be significantly military manpower intensive. How might DOD raise such a force while maintaining its standards? How do the tradeoffs between capability and capacity relate to the threats and scenarios undergirding the NDS?
• Will the United States be able to retain its alliances in their current forms while attracting new partners? One critical aspect of the strategic competition with China and Russia is their respective abilities to cause other international actors to doubt, if not reject, U.S. leadership. Should the United States prove unable to counter those challenges to American influence, how might that impact DOD's ability to effectively compete with each? How reliant is the strategy on our current allies and how might the United States seek to cultivate stronger and additional partners?
• What are the strategic and programmatic implications of the de-prioritization of climate change? Climate change and its national security ramifications were explicitly recognized by the Obama Administration as factors affecting the future global security environment and thus impacted capability and infrastructure investments. What, if any, programs or missions will be de-prioritized as a result of this decision? What are the security implications of these choices if they are made?