gunboat diplomacy, refers to the use or threat of military force, most often naval power, to influence or coerce other states without engaging in full-scale war. Rather than initiating sustained ground warfare or formal declarations of war, the practice relies on intimidation and the visible projection of force to pressure governments into negotiation, secure concessions, impose favorable trade terms, or shape political outcomes. It is most closely associated with the naval practices of imperial powers in the 19th and early 20th centuries, when pronounced imbalances of power and the absence of strong international constraints made such tactics especially effective.

Signals at sea: Gunboat diplomacy in the modern eraPeople watching the U.S. Navy guided-missile destroyer USS Gravely depart the Port of Spain, Trinidad and Tobago, on October 30, 2025. The warship had docked for joint exercises near the Venezuelan coast amid heightened U.S. pressure on Venezuela, illustrating how naval deployments continue to function as tools of diplomatic signaling.(more)

Following World War II, the expansion of international legal norms and the creation of collective security institutions placed new limits on the overt use of coercive force, contributing to the decline of traditional gunboat diplomacy as a routine tool of statecraft. Nevertheless, the concept has periodically resurfaced in debates over the role of military pressure in contemporary foreign policy.

Origins and historical practice The Big Stick eraIn the political cartoon “The Big Stick in the Caribbean Sea” (c. 1905), U.S. Pres. Theodore Roosevelt is depicted striding through the Caribbean, followed by a line of U.S. naval vessels. The image illustrates the logic of gunboat diplomacy, in which the visible presence of warships was used to enforce political influence and compel compliance.(more)

Gunboat diplomacy took a recognizable form in the mid-19th century, when advances in naval technology allowed industrial powers to project force far beyond their shores. Steam-powered warships, heavy naval artillery, and expanding imperial trade networks made maritime coercion an efficient instrument of foreign policy.

One of the most frequently cited examples occurred in 1853–54, when U.S. naval forces under Commodore Matthew Perry sailed a squadron of warships into Japanese waters to press for the opening of diplomatic and commercial relations between the two countries. Perry’s fleet, later known as the Black Ships, was prepared to employ force if necessary. However, Japanese officials, viewing the fleet as threatening, ultimately chose to negotiate, and the encounter resulted in agreements that ended Japan’s centuries-long policy of seclusion and opened the country to trade with the United States.

The Black Ships expedition was not an isolated episode but rather part of a broader 19th-century pattern in which naval superiority enabled industrial powers to shape political and economic outcomes abroad. Britain’s Royal Navy, for instance, was a dominant maritime force at the time and played a particularly prominent role in this system of power projection—an era that historians have termed Pax Britannica. British naval strength underwrote global trade routes and allowed London to enforce commercial access and diplomatic demands far from Europe. The First Opium War (1839–42) between Britain and China illustrates how this strategy operated in practice. British steam-powered warships, equipped with advanced artillery, overwhelmed China’s naval defenses and compelled China to accept the Treaty of Nanjing. That agreement ceded Hong Kong to Britain and opened additional Chinese ports to foreign trade. The episode demonstrated how maritime force could be used to secure treaty concessions and reshape economic relationships without full territorial occupation.

Naval power and crisis managementU.S. Pres. John F. Kennedy speaking to the country during the Cuban missile crisis, outlining the U.S. decision to impose a naval blockade of Cuba. The blockade highlighted the continued role of naval power in diplomacy, even as its use was increasingly constrained by the risk of escalation and nuclear conflict.(more)

The use of naval force as a means of exerting diplomatic pressure persisted into the early 20th century, particularly in U.S. relations with Latin America. During this period American economic interests abroad were frequently reinforced by military deployments, reflecting a broader pattern in which financial influence, or “dollar diplomacy,” and armed power operated in tandem. Following World War II, however, the establishment of the United Nations and the growing emphasis on state sovereignty and collective security placed new constraints on the overuse of intimidation. Decolonization and the expansion of international legal norms further reduced the acceptability of coercive naval diplomacy. Despite these changes, the underlying logic of force-based signaling did not disappear entirely. For instance, during the Cold War, naval power remained an important instrument of strategic communication, particularly in confrontations between the United States and the Soviet Union. One notable instance occurred during the Cuban missile crisis of 1962, when U.S. naval forces imposed a blockade around Cuba, creating a high-stakes environment in which naval pressure was used to influence political outcomes without triggering direct armed conflict.

Why gunboat diplomacy fell out of use

Gunboat diplomacy declined not because countries abandoned the use of force but because changes in the international system made naval intimidation less effective and more costly. After World War II the use of military force to impose political or economic demands increasingly conflicted with emerging legal norms that emphasized sovereignty and nonintervention. Even when not formally prohibited, such actions carried greater diplomatic and reputational consequences than they had in earlier periods.

Institutions and constraintThe United Nations headquarters in New York City symbolizes the post-World War II effort to regulate the use of military power through international law and collective security. Institutions such as the UN reduced the legitimacy of unilateral naval coercion by promoting norms of sovereignty, nonintervention, and multilateral decision-making.(more)

At the same time, shifts in the strategic environment reduced the utility of limited naval pressure as a controllable tool. The expansion of military alliances and the presence of nuclear weapons increased the risk that localized coercion could escalate beyond its intended scope. In this context demonstrations of naval force that once produced compliance could instead provoke countermeasures or international backlash. As a result, countries increasingly turned to alternative forms of pressure, including economic sanctions, multilateral diplomacy, and alliance-based deterrence. Naval power remained central to deterrence, crisis management, and enforcement of maritime law, but its explicit use to extract concessions outside of declared conflict became less routine.

Revisiting gunboat diplomacy in the modern era Gunboat diplomacy revisitedA Danish naval frigate patrolling off Nuuk, Greenland, amid heightened tensions after U.S. Pres. Donald Trump stated that the United States must obtain Greenland, raising concerns among Greenlandic, Danish, and European leaders about the possible use of force to pursue territorial claims.(more)

Although gunboat diplomacy declined as a routine instrument of statecraft after World War II, naval power continued to serve as a visible means of signaling resolve. Maritime patrols, freedom-of-navigation operations, and alliance exercises became common tools for deterrence and reassurance within a more institutionally structured international system. In these contexts, naval deployments were typically embedded within legal frameworks and alliance commitments rather than used unilaterally to extract concessions.

The United States Freedom of Navigation program provides a prominent example. In the South China Sea, where China asserts expansive maritime claims and has constructed artificial islands with military installations, U.S. naval vessels periodically sail through waters that Washington, D.C., regards as international under prevailing interpretations of maritime law. These operations are intended to assert navigational rights and challenge Chinese claims viewed as excessive, rather than to initiate hostilities. Warships are deliberately used to make a legal and political statement through physical presence at sea, demonstrating that maritime claims will not go uncontested.

Similar dynamics appear in the Taiwan Strait, where Chinese naval deployments function as visible demonstrations of strategic intent. Following visits by foreign officials to Taiwan or statements by Taiwanese leaders, Beijing has frequently responded with expanded naval exercises near the island. These operations have included warships crossing the informal “median line” that has long served as a practical boundary between the two sides. Such movements are widely interpreted as coercive signaling—intended to demonstrate maritime capability and reinforce Beijing’s sovereignty claim. The recurring presence of Chinese naval forces in the strait underscores its stated position that Taiwan falls within its territorial jurisdiction.

In recent years some observers have argued that certain U.S. actions have moved closer to earlier forms of gunboat diplomacy than to the more institutionalized model of naval signaling that characterized much of the postwar period. For example, during Pres. Donald Trump’s second term, U.S. forces employed limited but direct maritime coercion against Venezuela, including strikes on Venezuelan-linked vessels, the seizure of oil tankers, and a military operation that resulted in the capture of Pres. Nicolás Maduro.

The Trump administration’s rhetoric during this period frequently emphasized strength, deterrence, and military leverage as central components of diplomacy. Although these measures did not replicate 19th-century practices in full, some analysts contended that they echoed core features historically associated with gunboat diplomacy: the use of limited naval power, clear asymmetries of force, and pressure designed to shape political outcomes without sustained ground conflict.

“We live in a world, in the real world…that is governed by strength, that is governed by force, that is governed by power.” —Stephen Miller, deputy chief of staff for policy and homeland security adviser

This perspective was explicitly stated by senior White House adviser Stephen Miller, who argued that international politics remains fundamentally governed by power rather than norms. “We live in a world, in the real world…that is governed by strength, that is governed by force, that is governed by power,” Miller stated in an interview with CNN’s Jake Tapper, adding that these dynamics represent “the iron laws of the world that have existed since the beginning of time.” Such statements reflect a worldview that challenges the post-World War II assumption that legal constraints, international institutions, and collective security mechanisms have significantly altered the role of force in diplomacy.

“The jewel in the crown of our power and of our role in the world has always been our alliance system.” —Jeremy Shapiro, former U.S. State Department official

Other policymakers and analysts, however, have emphasized the enduring importance of those alliances and institutions and their legitimacy in shaping state power. Jeremy Shapiro, a former U.S. State Department official and fellow at the European Council on Foreign Relations, argued that “the jewel in the crown of our power and of our role in the world has always been our alliance system.” From this perspective, the effectiveness of military strength is closely tied to cooperation, credibility, and institutional support, rather than unilateral coercion alone. The contrast between these views highlights an ongoing debate over whether contemporary international politics reflects a return to force-centered diplomacy or a continued reliance on institutional frameworks that constrain and channel power.