Overview

The People's Republic of China (PRC, or China) claims but has never controlled Taiwan, a self-governing democracy of 23.4 million people located across the Taiwan Strait from mainland China. PRC leaders have stated their preference to unify peacefully with Taiwan, but have insisted on the right to use force to bring Taiwan under PRC control. U.S. policy toward Taiwan (which formally calls itself the Republic of China, or ROC) has prioritized the maintenance of peace and stability across the Taiwan Strait. For more than 75 years, the U.S. government has sought to strengthen Taiwan's and its own ability to deter PRC military aggression. The PRC, for its part, has claimed the United States uses Taiwan as a "pawn" to "contain" China. Congress has played a role in supporting U.S.-Taiwan defense ties, and has authorized new programs and appropriated funds to support Taiwan's defense since 2022. For more background on cross-Strait relations and U.S. policy toward Taiwan, see CRS In Focus IF10275, Taiwan: Background and U.S. Relations, by Susan V. Lawrence.

Figure 1. Taiwan

Source: Graphic by CRS.

Taiwan's Security Situation

The Communist Party of China's military, the People's Liberation Army (PLA), has undergone a decades-long modernization program focused primarily on developing the capabilities needed to annex Taiwan. Some observers assess that the PLA is, or soon would be, able to execute a range of military campaigns against Taiwan, including missile strikes, seizures of Taiwan's small outlying islands, blockades, and—what would be the riskiest and most challenging campaign for the PLA—an amphibious landing and takeover of Taiwan's main island. In 2023, then-director of the Central Intelligence Agency William Burns said PRC leader Xi Jinping had instructed the PLA "to be ready by 2027 to conduct a successful invasion" of Taiwan; Burns noted this was a goal related to military capabilities, not necessarily an indication of Xi's intent to start a war.

Among Taiwan's advantages in the face of the threat of PRC aggression is U.S. political and military support (see below). Another advantage is geography. The Taiwan Strait is roughly 70 nautical miles wide at its narrowest point, and weather conditions make the Strait perilous to navigate at certain times of the year. Taiwan's mountainous terrain and densely populated west coast are poorly suited for amphibious landing and invasion operations.

Taiwan's government has initiated programs to strengthen military readiness and increased its defense budget, which grew at an average rate of nearly 5% per year from 2019 to 2023. In 2024, Taiwan spent roughly 2.5% of its GDP on defense; Taiwan's president has said he intends to increase defense spending to more than 3% of GDP in 2025. President Donald Trump has suggested that Taiwan spend 10% of its GDP on defense.

Taiwan faces domestic challenges in realizing its defense goals, and its policymakers disagree over how best to deter the PRC from using force against Taiwan. While both of Taiwan's leading political parties say they support increased investment in Taiwan's defense, budget fights between its executive branch and opposition-controlled legislature in 2025 exacerbated concerns held by some about Taiwan's ability to ensure adequate defense funding. Taiwan's military struggles to recruit, train, and retain personnel, and some observers argue Taiwan's civil defense preparedness is insufficient. Taiwan's energy, food, water, communications, and other infrastructure is vulnerable to external disruption. At a societal level, it is not clear what costs—in terms of economic security, physical safety, and lives—Taiwan's people would be willing or able to bear in the face of a cross-Strait war.

PRC "Gray Zone" Activities Targeting Taiwan

In addition to training for large-scale military operations against Taiwan, the PRC engages in persistent non-combat operations that erode Taiwan's military advantages and readiness. These "gray zone" actions include frequent military exercises and near-daily patrols in the vicinity of Taiwan (including frequent sorties across the so-called "median line," an informal north-south line bisecting the Strait that PLA aircraft rarely crossed prior to 2022); cyber operations; uncrewed combat aerial vehicle flights encircling Taiwan; and stepped-up law enforcement activities near the Taiwan-administered Kinmen Islands located just off the PRC coast. These activities offer the PLA training and intelligence-gathering opportunities and strain Taiwan's forces, which face growing operational and maintenance costs from responding to PLA activities.

The normalization of PLA operations ever closer to Taiwan's islands in peacetime could undermine Taipei's ability to discern whether the PLA is using such activities to obscure preparations for an attack. Gray zone tactics could also have strategic value for the PRC. Some observers assess the PRC uses these activities to sow doubt about Taiwan's military capabilities among Taiwan civilians and to create political pressure for Taipei to acquiesce to Beijing's insistence on unification. Many observers believe PRC leaders may prefer to gradually assume control over Taiwan through gray zone coercion and political warfare rather than to risk a large-scale conflict that could possibly draw the PRC and the United States—two nuclear powers—into war.

U.S. Support for Taiwan's Defense

The United States has maintained unofficial defense ties with Taiwan since the United States terminated diplomatic relations with the ROC in 1979 and a mutual defense treaty in 1980. The defense relationship encompasses arms transfers, routine bilateral defense dialogues and planning, and military training.

A challenge for U.S. policymakers is supporting Taiwan's defense without triggering the conflict that U.S. policy seeks to prevent. PRC leaders have warned their U.S. counterparts that Taiwan is "the first red line that cannot be crossed" in U.S.-China relations. The PRC has responded to U.S. military support for Taiwan and high-level U.S.-Taiwan engagements by accusing the United States of "playing with fire," and by escalating gray zone coercion against Taiwan. Following then-Speaker of the House Nancy Pelosi's 2022 visit to Taiwan, the PRC stepped up military operations near Taiwan and established a "new normal" for the PLA's presence in the area.

U.S. Strategy and Policy

The 1979 Taiwan Relations Act (TRA, P.L. 96-8; 22 U.S.C. §§3301 et seq.) includes multiple security-related provisions. Among other things, the TRA states that it is U.S. policy to "make available to Taiwan such defense articles and defense services in such quantity as may be necessary to enable Taiwan to maintain a sufficient self-defense capability" and "to maintain the capacity of the United States to resist any resort to force or other forms of coercion that would jeopardize the security, or the social or economic system, of the people on Taiwan."

The TRA does not require the United States to defend Taiwan, but by stating it is U.S. policy to maintain the capacity to do so, the TRA creates "strategic ambiguity" about potential U.S. actions in the event of a PRC attack. Some observers advocate making a more formal U.S. commitment to defend Taiwan. Supporters of such a shift argue that "strategic clarity" is necessary to deter an increasingly capable and assertive PRC. Supporters of strategic ambiguity argue that the long-standing policy encourages restraint by both Beijing and Taipei and incentivizes Taipei to invest more in its own defense.

Successive U.S. administrations have encouraged Taiwan to pursue an "asymmetric" defense strategy (sometimes called a "porcupine strategy"), the goal of which is to make Taiwan difficult for the PRC to quickly subdue or "swallow." This approach envisions Taiwan investing in capabilities intended to stymie an amphibious invasion through a combination of anti-ship missiles, naval mines, and other similarly small, distributable, and relatively inexpensive weapons systems. Taiwan's government has adopted this approach to some extent, but some (including stakeholders in Taiwan's defense establishment) argue that Taiwan must continue to invest in conventional capabilities (e.g., fighter jets and large warships) to deter gray zone coercion short of an invasion. Uncertainty as to whether, how, and for how long the United States might aid Taiwan in the event of a cross-Strait war informs these debates.

Arms Transfers and Security Cooperation

U.S. arms transfers have been the most concrete U.S. contribution to Taiwan's defense capabilities. Most of these transfers are Foreign Military Sales (FMS). From 2015 to 2025, the executive branch notified Congress of more than $28 billion in FMS to Taiwan.

Beyond FMS, the 117^th Congress authorized new avenues to transfer arms to Taiwan with the Taiwan Enhanced Resilience Act (TERA; Title LV, Subtitle A of the James M. Inhofe National Defense Authorization Act [NDAA] for FY2023, P.L. 117-263). TERA made Presidential Drawdown Authority (PDA; 22 U.S.C. 2318(a)(3)) available to Taiwan for the first time, authorizing the provision to Taiwan of defense articles and services directly from U.S. Department of Defense (DOD) stocks. The provision reflected congressional concerns about long FMS delivery timelines. Since TERA's enactment, the executive branch has announced three PDA packages for Taiwan totaling $1.5 billion. TERA also for the first time authorized the provision of Foreign Military Financing (FMF; 22 U.S.C. 2763; essentially, loans or grants a foreign government may use to purchase U.S. arms) for Taiwan. Since then, Congress has appropriated funds for FMF to Taiwan through TERA and other authorities.

U.S.-Taiwan security cooperation includes training in the United States and in Taiwan, which, although generally not widely publicized, appears to be expanding. Taiwan began receiving training through the International Military Education and Training (IMET) program in 2023.

The 118^th Congress established the Taiwan Security Cooperation Initiative (TSCI) in the FY2025 NDAA (P.L. 118-159), authorizing assistance to "enable Taiwan to maintain sufficient self-defense capabilities." The FY2026 NDAA bills reported out of the House and Senate armed services committees include provisions related to Taiwan and the TSCI. The House Committee on Armed Services-reported bill would authorize $1 billion for the TSCI for FY2026; the House-passed DOD Appropriations Act, 2026 (H.R. 4016) would appropriate $500 million for the TSCI, $100 million more than the FY2025 enacted level. The President's FY2026 budget request includes $1 billion for the TSCI.