Experts React: The NSS and Washington’s New Approach to the Western Hemisphere

Commentary by Ryan C. Berg, P. Michael McKinley, Christopher Hernandez-Roy, Juan Cruz, and Eric Farnsworth

Published December 10, 2025

Last week, the Trump administration released its second National Security Strategy (NSS) document. The document is less a blueprint for action than it is a statement of the administration's ambitions for the world it would like to see. What emerges immediately upon review of the document is an articulation of the administration's intense focus on the Western Hemisphere. Below, CSIS Americas Program experts react to various elements of the 2025 NSS.

Paradigm Shift: Western Hemisphere Priorities in the 2025 NSS | Ryan C. Berg

How to Read the NSS and its Policy Influence | P. Michael McKinley

Counternarcotics as a Central Pillar of U.S. Strategy in the Western Hemisphere | Christopher Hernandez-Roy

Understanding the "Trump Corollary" to the Monroe Doctrine | Juan Cruz

U.S.-China Economic Competition and Economic Security Initiatives in Latin America | Eric Farnsworth

Paradigm Shift: Western Hemisphere Priorities in the 2025 NSS

Ryan C. Berg, Director, Americas Program

In many ways, the NSS concretizes what Secretary of State Marco Rubio outlined in an article for the Wall Street Journal regarding an "Americas First Foreign Policy." As a region, the Western Hemisphere features prominently. In NSS documents past, the Western Hemisphere receives nary two pages of treatment, while in this iteration, it receives four. Furthermore, the Western Hemisphere is the first region addressed, suggesting its prominence in the Trump administration's strategy and defense of the homeland. The document also highlights the administration's three priority areas-drugs, migration, and great power adversaries in the United States' shared neighborhood.

Stepping back, the 2025 NSS suggests the United States believes it is in the "consolidation phase" of the contest between great powers in the twenty-first century, following past National Security Strategies that declared the dawn of great power competition, then divided the world between autocracies and democracies. In the consolidation phase, rival powers are likely girding themselves, solidifying their immediate neighborhoods, demanding more of their alliances, and institutionalizing the competitive environment across diplomatic, economic, technological, and military domains. The 2025 NSS appears to speak to these concerns.

Perhaps the biggest announcement is the assertion of a "Trump Corollary" to the Monroe Doctrine, which seeks to deny extra-hemispheric competitors the ability to threaten the U.S. homeland from the Western Hemisphere. The document decries past failures to push back on extra-hemispheric competitors in the Western Hemisphere, presaging a more assertive and involved United States than in decades past.

How to Read the NSS and its Policy Influence

P. Michael McKinley, Senior Adviser (Non-resident), Americas Program

NSS documents should be taken seriously. They lay out how an administration sees the priorities, aspirations, and challenges for the foreign policy of the United States at a given point in time. The NSS released on December 5 by the White House does just that, and something more: It formalizes the move underway from more global objectives to the primacy of an U.S. security strategy that focuses on national economic resiliency, borders, and defense.

This NSS therefore mirrors the significant shift in foreign policy priorities since the beginning of the year. "Liberation Day" on April 2, 2025, changed the relationship of the global economy with the U.S. market, now more intent on internal transformation. Both the Pacific and trans-Atlantic security alliances have had to address the concerns of the administration about burden-sharing, and there is a greater emphasis by the United States on security in the Western Hemisphere. The United States is also changing the way it interacts with the international multilateral system on several transnational issues, as it also cuts overseas assistance to focus on domestic priorities. No region in the world is likely to experience the emerging nexus of U.S. national and foreign policy priorities more than the Western Hemisphere.

Counternarcotics as a Central Pillar of U.S. Strategy in the Western Hemisphere

Christopher Hernandez-Roy, Deputy Director and Senior Fellow, Americas Program

For an administration that has made stopping the flow of illegal drugs to the United States a centerpiece of its foreign policy, whether by applying early tariffs on Canada and Mexico to get them to do more to combat fentanyl trafficking, and more recently, deploying an armada to the southern Caribbean to eliminate alleged drug boats carrying cocaine, it is fitting that the NSS should explicitly declare that it will protect Americans from the scourge of drugs.

The NSS seeks to enlist regional champions in the Western Hemisphere to stop drug flows and neutralize cartels. Countries that answer the call will be rewarded with nearshoring investments and other economic opportunities. For many countries in the region plagued by unprecedented levels of violence related to transnational criminal activity, greater counter-narcotics cooperation with the United States is welcome, so long as it is rules-based and centered on reciprocity and respect for sovereignty. Countries should frame the cooperation as a shared responsibility, emphasizing that while the flow of drugs moves north, weapons and illicit finance move south, leaving victims in both geographies. The U.S.-Mexico Security Implementation Group, established by the two countries through an agreement reached in early September, offers a possible model.

Rather than wait and react to U.S. pressure, partners should be proactive and offer to serve as regional champions, tabling integrated cooperation proposals that combine enforcement with intelligence sharing, target illicit finance, harden ports and borders, and improve chemical controls. Several partners, including Argentina, the Dominican Republic, Ecuador, Paraguay, Peru, and Trinidad and Tobago, have already declared Tren de Aragua or the Cartel de los Soles to be terrorist organizations, signaling an alignment with Washington and a desire to increase counter-drug cooperation. A spate of recent elections and those in 2026 are likely to bring to power more Washington-friendly governments that will find a willing partner on security cooperation.

Understanding the "Trump Corollary" to the Monroe Doctrine

Juan Cruz, Senior Adviser (Non-resident), Americas Program and Director, Argentina-U.S. Strategic Forum

While the 2025 NSS explicitly declares that the United States will "assert and enforce a 'Trump Corollary' to the Monroe Doctrine," it may not, in fact, represent a meaningful shift toward the Western Hemisphere, per se, but instead merely articulate an America First foreign policy. The strategy codifies the Trump campaign platform, puts words into practice, and elevates counternarcotics to a national security imperative to secure U.S. borders, control transit routes, stop drug flows, and neutralize and defeat cartels before they reach the U.S. homeland. Directly tied to narrow and specific U.S. interests, as they relate to the Western Hemisphere, the strategy resoundingly concentrates all tools-military being essential here-to promote a forward-leaning, pragmatic, and tightly defined agenda that defends U.S. territory, guarantees security of its citizens, and protects U.S. economic and commercial interests.

Focusing on the transactional, the strategy pinpoints the dynamics within the region that intersect with U.S. security, economic, and geopolitical concerns and signals not so much a renewed hemispheric vision, but a clearer and more disciplined assertion of current national security imperatives framed through an America First lens. What's more, in addition to securing U.S. borders and controlling and deterring illegal and unwanted migration, the Trump administration prioritizes strengthening select regional security partnerships aimed at disrupting drug trafficking, dismantling transnational criminal organizations and networks, and reducing illicit flows, as well as advancing commercial diplomacy for the protection of critical assets, supply chains, and key infrastructure from influence by hostile non-hemispheric competitors (e.g., China, Iran, and Russia).

This strategy establishes U.S. preeminence in the region, sets expectations for friends and adversaries alike, and makes clear that the United States will not hesitate to aggressively use its military might to counter narcotics trafficking. Moreover, it conveys that the American people deserve the best and underscores that "allowing these incursions without serious pushback is another great American strategic mistake of recent decade." This comment, without doubt, sends a message to Beijing to keep its hands off the Western Hemisphere.

U.S.-China Economic Competition and Economic Security Initiatives in Latin America

Eric Farnsworth, Senior Associate (Non-resident), Americas Program

The document not only highlights China's growing presence across the region but explicitly says the United States will resist it. In particular, Washington will take a much more aggressive posture to deny China access to strategic assets considered dual-use in nature (e.g., ports). Efforts to reframe security issues around the Panama Canal, deep space tracking capabilities in Argentina, and amplified focus on the procurement of U.S. or U.S.-adjacent military and cyber products are consistent with this new approach. So, too, are efforts to stanch the flow of fentanyl supply from China through Mexico and strengthening provisions in trade agreements, including the United States-Mexico-Canada Agreement, to extricate China from regional supply chains.

On trade, the region should anticipate greater efforts at the customs level to reduce transshipments of products from China and the continued use of tariffs from the Trump administration as leverage. Meanwhile, a focused effort to encourage private sector-led investment in the region to recapture momentum from China is fully consistent with the administration's regional engagement and economic security strategy.

Commentary is produced by the Center for Strategic and International Studies (CSIS), a private, tax-exempt institution focusing on international public policy issues. Its research is nonpartisan and nonproprietary. CSIS does not take specific policy positions. Accordingly, all views, positions, and conclusions expressed in this publication should be understood to be solely those of the author(s).

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