In what has become one of the most significant escalations in the Taiwan Strait in recent years, the Trump administration's approval of an $11.1 billion arms package to Taiwan, the largest single weapons deal in U.S. history with the island, set off a chain of events that brought the region to a level of military tension not seen since 2022. Within days of the announcement, China deployed its army, navy, air force, and rocket units in what it named "Justice Mission 2025," the most geographically extensive military exercises Beijing has ever conducted around Taiwan.
The Arms Sale: What Was Approved and Under What Legal Framework
On December 17, 2025, the U.S. Defense Security Cooperation Agency notified Congress of eight potential Foreign Military Sales cases to Taiwan, covering 82 High Mobility Artillery Rocket Systems (HIMARS) and 420 Army Tactical Missile Systems (ATACMS) valued at up to $4.05 billion, 60 M109A7 Self-Propelled Howitzers valued at up to $4.03 billion, and Altius Autonomous Air Vehicles valued at up to $1.1 billion. The package also included military software valued at more than $1 billion, Javelin and TOW missiles worth more than $700 million, helicopter spare parts worth $96 million, and refurbishment kits for Harpoon missiles worth $91 million.
This was not a discretionary policy choice made in isolation. The legal foundation for the sale rests on the Taiwan Relations Act (TRA), enacted on April 10, 1979, which requires the United States to maintain a policy of providing Taiwan with arms of a defensive character 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 social or economic system of the people on Taiwan. Under the Act, the United States is obligated 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.
The sale followed Congress's passage of the 2026 National Defense Authorization Act (NDAA), which authorized up to $1 billion in funding for Taiwan's defense. With this new package, the total dollar value of the U.S. arms sale backlog to Taiwan rose to approximately $32 billion, with at least $4.4 billion of that amount already partially delivered to Taiwan. Taiwan's Ministry of National Defense expressed sincere gratitude to the United States, noting that the Trump administration had made a notification to Congress to process the sale. Taiwan's President Lai Ching-te had announced in November 2025 a supplementary defense budget of $40 billion to run from 2026 to 2033, with declared intent to build an air defense architecture modeled on Israel's Iron Dome system.
China's response was immediate and categorical. China's Ministry of Foreign Affairs stated that the sale "grossly violates the one-China principle," undermines stability in the region, and "sends a gravely wrong signal to 'Taiwan independence' separatist forces," adding that "China firmly opposes and strongly condemns it." Beijing additionally sanctioned 20 American companies and 10 executives in direct retaliation for the transaction.
Justice Mission 2025: Scope, Deployment, and Military Dimensions
China's "Justice Mission 2025" exercises, conducted from December 29 to 30, 2025, were the eighth major military drill held around Taiwan since the beginning of the Fourth Taiwan Strait Crisis in August 2022, and notably the first that had a publicly stated aim of deterring external involvement.
China's Eastern Theatre Command deployed troops, warships, fighter jets, and artillery, with the stated objectives of encircling the island, conducting live fire and simulated strikes on land and sea targets, and blockading Taiwan's main ports. The exercises saw China deploy naval destroyers, frigates, fighter planes, bombers, drones, and long-range missiles to simulate seizing control of Taiwan's airspace, blockading its ports, and striking critical infrastructure, mobile ground targets, and maritime targets.
The exercises initially designated five zones for live-fire drills, which China's Maritime Safety Administration later expanded to seven. The zones crossed into Taiwan's territorial waters for the first time since the 2022 exercises. Taiwan's Ministry of Defence tracked 130 air sorties by Chinese aircraft, 14 naval ships, and eight official ships between 6 a.m. on Monday and 6 a.m. on Tuesday, with 90 of the air sorties crossing into Taiwan's air defence identification zone. On the second day of the drills, rockets were fired from Pingtan Island, marking the first time China had fired rockets into the Taiwan Strait since the 2022 exercises. Taiwan's Ministry of National Defense stated the rockets landed near Taiwan's 24 nautical mile line. Taiwan's transport ministry said over 100,000 passengers set to take international flights were affected by the drills, while nearly 80 domestic flights were cancelled.
The exercise was distinguished by high levels of aviation activity, the deployment of more advanced PLA Navy amphibious ships, and declared exercise operating areas that were closer to Taiwan's contiguous zone than in any previous drill. Analysts at the Taiwan Security Monitor noted that the zones were particularly large in the southern and southeastern areas, breaching territorial waters.
Legal Disputes, International Reactions, and the Path Ahead
The arms sale and subsequent drills have sharpened a long-running legal dispute at the heart of U.S.-China-Taiwan relations. China has argued that U.S. arms sales to Taiwan directly contradict Washington's obligations under the Three Communiqués with Beijing, particularly the August 17, 1982 communiqué, in which the United States pledged that it would gradually reduce arms sales to Taiwan. Washington, for its part, has maintained that the Taiwan Relations Act takes precedence and has not formally recognized Beijing's sovereignty claims over Taiwan under any of the three communiqués. On February 4, 2026, Chinese President Xi Jinping raised concerns about U.S. arms sales to Taiwan during a phone call with President Trump, urging the U.S. to handle the matter with "utmost caution," and reiterating that China would never allow Taiwan to be separated from it. Ahead of a scheduled meeting between Trump and Xi in Beijing on May 14 and 15, 2026, diplomatic readouts confirmed that U.S. arms sales to Taiwan are among the principal issues on the agenda.
International reactions to the drills covered the spectrum. The European Union's External Action Service said the exercises "increase cross-strait tensions and endanger international peace and stability," while Japan conveyed its concerns to China and called for peaceful resolution through dialogue. Australia's Department of Foreign Affairs stated that it "strongly opposes any actions that increase the risk of accident, miscalculation or escalation."
Taiwan's government condemned the exercises. President Lai Ching-te described China's escalation of military pressure as part of an ongoing cognitive warfare campaign. The Mainland Affairs Council said the exercises disrupted Taiwan's civil aviation and maritime traffic.
Analysts have noted that Beijing's drills increasingly blur the line between routine military training and stage-setting for an attack, a strategy intended to give the United States and its allies minimal warning of a potential military action. The structural tension underpinning this standoff is unlikely to be resolved quickly. The United States maintains legal obligations to arm Taiwan. China maintains that the island is an internal matter. And Taiwan continues to build its defenses against an adversary that has conducted eight rounds of major military exercises around it in the span of three years.
The Taiwan Strait remains one of the most watched maritime corridors in the world and on current trajectory, the scrutiny is only set to grow.
