The first National Security Strategy of the United States of America was released in 1950 under President Truman. It set firm strategic goals based on the containment doctrine to limit the influence of communist ideology in the global order. This first national security strategy marked the beginning of limited global policing in US geopolitics, but it was less pragmatic and more principled realism. American interests became specific to liberal internationalism and focused only on areas facing the spread of the communist threat.
The Core Security Thinking of the US
The core security thinking of Americans was to preserve their sphere of influence from any adversarial influence or intervention, echoing the Monroe Doctrine. The initial period had this core, and the first national security strategy laid the groundwork for this security thinking. In 1988, the scope of core security thinking expanded, and elements of realism advanced further, with the US beginning to engage in deterrence calculations and global outreach to build collective military alliances against the Soviets. Most importantly, the strategy also focused on strengthening the economy. The core security thinking in the US’s national security strategy by the late 1980s began to realize that, while the Monroe Doctrine is important, US strategic interests must also require adopting flexibility in its confrontational approach, guided by liberal internationalism and the containment of communism.
Pragmatism and Realism
After the Soviet disintegration, US National Security Strategy focused on navigating a multipolar world by reinforcing the idea of collective security under the H.W. Bush Administration. The 1991 and 1993 US National Security strategies expanded on the concepts that started to emerge in the late 1980s—deterrence and engagement. In the 1990s, this strategy was continued through Powell’s four pillars: strong defense, forward presence, alliances, and coalition-building. The national security strategy designs suggest that elements of pragmatism and distinctions of pure realism gradually began to take center stage in the US national security approach.
Strategy in Crises
The National Security Strategy changed after 9/11, possibly in response to shifted security priorities. The previous approach of principled realism, which involved pragmatic and defensive tactics, now showed a slight shift, with the US’s national security strategy emphasizing more openly offensive realism and dogmatism. By the mid-2000s, the US had reactionary national security strategies, moving away from the approach that began to develop in the late 1980s. Key shifts in security strategies after 2001 included the doctrine of preemption and unilateral actions, but another significant change was a major shift in the collective engagement perspective, differing from earlier ideas of shared strategic responsibilities among allies.
After 9/11, the US called on allies, particularly in NATO, to bear a greater share of the burden for collective defense efforts, shifting away from reliance solely on the US. The core security thinking, rooted in peace through engagement, shifted during the 1990s toward peace through strength. Another aspect, after the Monroe Doctrine, peace through strength, gained a label of permanence in the US National Security Strategy, though its effectiveness and emphasis varied over time.
Trump’s National Security Strategy: Rebooting and Readjustments
Trump’s 2025 national security strategy resembles his 2017 National Security Strategy. The nationalist ideals of America First and the focus on economic engagement—which is the main security approach this time—are a mix of realizations and reactions. The first reaction to the current global situation is reasserting the Monroe Doctrine, dubbed “Trump Corollary,” and the second is showing the will for peace through strength by deterrence. Even if conflicts occur, the strategy emphasizes engaging in conflict with strategic skill to quickly win wars with little to no casualties. The realization part of the strategy is the US increasing its understanding of collective efforts and economic strength. The strategy highlights stronger partnerships with countries like India for the Indo-Pacific.
Reaction and Challenge
The realistic approach in this strategy is flexible realism, aiming not at domination but at maintaining a balance of power, while not fully adopting defensive realism. The United States has embraced both offensive and defensive realism. Over the past ten years, the US National Security Strategy under Obama, Trump 1.0, and Biden has incorporated elements of defensive realism along with principled realism, with the US gradually increasing its efforts to balance power through the promotion of liberal and pro-democratic values—examples include its Middle East policy and the revival of QUAD in 2017. However, a notable development in the 2025 strategy is the US’s willingness to undertake offensive actions to maximize security, such as Operation Midnight Hammer against Iran and expanding operations in Latin America against Venezuela. Another prominent aspect of this strategy is the US’s focus on Europe’s burden-sharing, attempting to lighten its responsibilities and emphasizing that Europe should stand on its own, while the US remains a facilitator in Europe’s development. However, it is no longer willing to assume a broader role—similar to sentiments after 9/11. This strategy likely reflects the challenges posed by a rising China, Russia’s multipolar approach, and increasing strategic competition in multilateral arenas. The Trump approach—as mentioned in the strategy—is not just a reboot of the US National Security strategy after the 2000s but with some realizations.
Realization
There is a growing realization, as highlighted earlier, that the US can no longer sustain a confrontational approach and aggressive, offensive realism. The Trump strategy for 2025 recognizes the need to incorporate elements from both the late Cold War and post-Cold War periods. The latter was characterized by defensive realism and principal realism features—approaches that the US emphasized during the Clinton years, when embracing multilateralism, economic diplomacy, and regional collective engagements became central to US national security strategy, paving the way for more pragmatic interventions. A similar recognition of Clinton’s policy of enlargement through engagement is reflected in Trump 2.0 National Security Strategy—Shifting from Aid to Trade with Africa, which exemplifies this focus on promoting economic diplomacy and broadening engagement.
The US National Security Strategy 2025 reflects the nation’s understanding of how to adapt its engagement with the global order while maintaining realism. This time, US security thinking appears to find a balance between engagement and deterrence, which in previous years often seemed to conflict.