By Zarak Khan | 2025-12-10

The United States is taking a more visible posture in the South China Sea, responding to what officials and analysts describe as a sustained campaign of Chinese coercion that is heightening tensions in one of the world's busiest maritime corridors.

Recent high-profile freedom of navigation operations (FONOPs) represent one of Washington's more visible efforts to counter Beijing's sweeping maritime claims, which have been rejected by an international tribunal and many governments.

US and allied security officials say Beijing's efforts to enforce control over vast stretches of the disputed South China Sea lack any basis under international law.

These operations routinely contest those efforts, including Beijing's requirement that foreign warships obtain prior authorization before exercising innocent passage through its claimed territorial sea.

That obligation is incompatible with the United Nations Convention on the Law of the Sea (UNCLOS) provisions guaranteeing innocent passage without advance notification, US officials note.

The patrols are essential to safeguarding the global maritime order and preventing "unlawful and sweeping maritime claims" that threaten the freedom of the seas, including navigational freedoms, free trade and unimpeded commerce and freedom of economic opportunity for South China Sea littoral nations, according to Washington.

Heightened Chinese anxiety

For its part, Beijing has repeatedly denounced the intensification of US patrols, issuing increasingly forceful statements that US officials and many legal scholars say misrepresent the legal basis of American operations and are aimed at contesting the legitimacy of US maritime operations.

Following several recent US transits of the Taiwan Strait, the Chinese People's Liberation Army (PLA) asserted that it "drove away" American warships from what it says are China's territorial waters, a portrayal US officials reject as inconsistent with events and international law.

These criticisms resurfaced in August when the guided-missile destroyer USS Higgins (DDG-76) conducted a FONOP near Scarborough Shoal, a disputed maritime feature claimed by China, Taiwan and the Philippines that has has long served as a pressure point in China's strategy to tighten control over contested waters and advance its regional power projection.

The USS Higgins on August 13 sailed within 12 nautical miles of the shoal, just two days after two Chinese vessels collided while pursuing a Philippine coast guard ship in the area.

It was the first US operation near Scarborough Shoal since 2019 and the second South China Sea FONOP by the United States this year, according to US Naval Institute News.

China's Southern Theater Command accused the US Navy of "illegally" entering Chinese territorial waters and again asserted that PLA vessels "drove away" the American destroyer.

The US Navy dismissed the Chinese statements, stressing that the USS Higgins operated "in accordance with international law."

"The operation reflects our commitment to uphold the freedom of navigation and lawful uses of the sea as a principle. The United States is defending its right to fly, sail and operate wherever international law allows, as USS Higgins did here," said a spokesperson for the US 7th Fleet in a statement.

"Nothing China says otherwise will deter us."

Legal disputes intensify

For their part, Chinese state-run outlets and affiliated research centers have also issued reports attempting to deem US FONOPs illegal.

In August, the China Institute for Marine Affairs under the Ministry of Natural Resources released a legal report asserting that US FONOPs lack grounding in international law and represent an American practice of using military force to pressure other states.

However, legal scholars have described China's arguments as baseless attempts to undermine FONOPs.

An August analysis in the EurAsian Times noted that "an unbiased reading of the UNCLOS" ran counter to the Chinese report, reaffirming that "Freedom of Navigation laws under ... [UNCLOS] allow ships from any country to sail through international waters without interference."

The report added that under UNCLOS, waters beyond the 12-nautical-mile territorial sea, including Exclusive Economic Zones, are not subject to full coastal-state sovereignty and foreign ships enjoy broad freedoms of navigation there. In territorial seas, they retain the right of innocent passage. "This same law also applies to the South China Sea," it said.

FONOPs are not directed solely at China.

During Fiscal Year 2023, US forces challenged 29 maritime claims advanced by 17 different states worldwide.