Ju Eun-sik, President of the Korea Institute for Strategic Studies 1950s: The Eisenhower Administration and the Strategy of Massive Retaliation

In the aftermath of World War II, the United States had to secure military superiority in the context of the Cold War with the Soviet Union. The Eisenhower administration adopted the strategy of Massive Retaliation, centering its strategy on the overwhelming superiority of nuclear weapons. This was a strategy aimed at achieving war deterrence by threatening nuclear retaliation regardless of how the Soviet Union attacked in Europe or Asia. While this strategy was cost-effective, it was criticized for its lack of flexibility due to the risk of local conflicts escalating into nuclear war.

1960s: The Kennedy Administration's Flexible Response Strategy and the Concept of Two-and-a-Half Wars

The Kennedy administration proposed the Flexible Response strategy to overcome the limitations of the Massive Retaliation strategy. This strategy allowed for phased responses using various options, from conventional forces to nuclear weapons, depending on the crisis. Simultaneously, the United States established the "Two-and-a-Half Wars concept" to secure the capability to handle large-scale wars in Europe and Asia alongside limited conflicts in the Third World. To this end, conventional forces were augmented, special forces like the Green Berets were deployed, and rapid mobility capabilities were enhanced.

1970s: The Nixon, Ford, and Carter Administrations' One-and-a-Half Wars Concept

Amidst war fatigue and financial burdens stemming from the prolonged Vietnam War, the "Nixon Doctrine" was announced, encouraging allies to strengthen their own security. Consequently, the United States adjusted its strategy to the "One-and-a-Half Wars concept," scaling back its objective to be able to simultaneously conduct large-scale warfare in one major theater and minor conflicts in regions like the Middle East. The Carter administration established the Rapid Deployment Force (RDF) in response to the Soviet invasion of Afghanistan, enhancing its capability to respond to Middle Eastern crises.

1980s: The Reagan Administration's Concept of Multi-Regional Global Warfare and the Strategic Defense Initiative (SDI)

The Reagan administration actively responded to the Soviet Union's military buildup and pursued the concept of Multi-Regional Global Warfare. It prepared for the possibility of simultaneous wars breaking out in Europe, the Middle East, and the Far East, modernizing both conventional and nuclear forces. Notably, the Strategic Defense Initiative announced in 1983 was a concept for a missile defense system capable of intercepting Soviet nuclear missile attacks, which shook the strategic balance of the Soviet Union, particularly its air defense systems, and accelerated the arms race, contributing to the end of the Cold War. This strategic concept was led by Andrew Marshall of the Pentagon's Office of Net Assessment.

1990s: The Clinton Administration's Win-Win Strategy

With the end of the Cold War, the United States emerged as the sole superpower. The Clinton administration, after its defeat in the Vietnam War, undertook reforms, regained confidence with its victory in the Gulf War based on the air-land battle doctrine, and established the Win-Win strategy, aiming to maintain the capability to win both large-scale wars that could occur simultaneously in the Middle East and on the Korean Peninsula. During this period, the U.S. military, through the Revolution in Military Affairs (RMA), developed precision-guided munitions and C4ISR systems to realize Network-Centric Warfare (NCW).

2000s: The Bush Administration's 1-4-2-1 Strategy

Following the 9/11 terrorist attacks, the Bush administration declared the "War on Terror" and presented a new military strategy. The 1-4-2-1 strategy consists of: 1: Homeland defense; 4: Forward-deployed deterrence in Europe, the Middle East, Northeast Asia, and Southeast Asia; 2: Defeating enemies in two theaters; 1: Achieving decisive victory in one of the two theaters. This strategy supported the conduct of the wars in Iraq and Afghanistan and opened the possibility of preemptive strikes against potential threats.

2010s: The Obama Administration's 1+ Strategy and the Pivot to Asia

The Obama administration pursued the "1+" strategy to reduce the burden of prolonged wars and build a sustainable security model. This concept involves conducting operations in one major theater while maintaining deterrence in another. Furthermore, starting in 2011, the "Pivot to Asia" policy was fully implemented to counter China's rise and strengthen the U.S. military's presence in the Indo-Pacific. The role of drones, cyber warfare, and special operations forces expanded.

2020s: The Trump Administration's Great Power Competition Strategy and Defense Reform

Since 2017, during the first term of the Trump administration, U.S. military strategy was reorganized around "Great Power Competition." The National Defense Strategy (NDS) released in 2018 shifted focus away from the War on Terror, identifying China and Russia as "Revisionist Powers" and long-term changers of the status quo. This strategy emphasized strengthening homeland defense, maintaining U.S. military superiority in the Indo-Pacific, increasing defense burden-sharing by allies, and building a comprehensive competitive posture that includes economic, technological, and industrial foundations. The Aria Act (Asia Reassurance Act) was passed.

Trump secured superiority in space by creating the Space Force and enhanced capabilities to respond to asymmetric threats by elevating the Cyber Command.

The Space Force was established to secure superiority in the space domain, and the Cyber Command was elevated to enhance capabilities to respond to asymmetric threats. Furthermore, under the "America First" principle, the administration sought to expand the responsibilities of allies by demanding significant increases in defense cost-sharing. In terms of military operations, the focus shifted from large-scale ground wars to long-range precision strikes, strengthening naval and air power, and developing advanced weapons (F-35, hypersonic weapons). While this created tensions in alliance relationships, it further tightened security cooperation with South Korea, Japan, and Australia as a key pillar of the Indo-Pacific strategy.

Biden's Integrated Deterrence and Multi-Domain Operations (MDO)

While inheriting Trump's Great Power Competition strategy, Biden placed alliance restoration and the revival of multilateralism at the strategic center. The National Security Strategy (NSS) and National Defense Strategy (NDS) released in 2022 defined China as the "sole comprehensive competitor," North Korea as an "expander of illicit nuclear weapons development and missile programs," and Russia as an "immediate and serious threat." Biden proposed a new concept called Integrated Deterrence, going beyond simple military buildup. In this context, strategic competition was viewed as a competition between democracies and autocracies, adopting a two-track approach that involves cooperating with all countries while strengthening cooperation with democratic nations.

Strategic Comprehensive Evaluation and the Reason for Renaming the War Department

U.S. military strategy has evolved from a Cold War-era focus on nuclear deterrence to multi-theater responses, intervention in local conflicts, counter-terrorism operations, and most recently, a long-term strategic competition with China and Russia. Trump's strategy evolved into a comprehensive national strategy that encompasses not only military operations but also economic, technological, and alliance structures. In this process, the U.S. has sought to forge a new strategic balance by demanding greater responsibility from NATO and its allies while strengthening its military presence in the Indo-Pacific.

Before announcing the National Defense Strategy, Trump signed an executive order to rename the Department of Defense to the War Department, a name used until 1947, after 78 years. Trump argued that he won World Wars I and II under the War Department and that renaming it the Department of Defense was a move aimed at enhancing the military's combat readiness and achieving political effects through strength, but it incurred costs for changing numerous Department of Defense emblems. This is considered a preparatory step in the strategy to encircle China, actively preparing for a Taiwan contingency in addition to defending U.S. territory.