The Navy destroyer USS Curtis Wilbur passed within 12 nautical miles of Triton Island, the southernmost of the Paracel Islands, on January 30 in the second operation in the South China Sea in recent months under the Department of Defense’s Freedom of Navigation Program. And despite significant disappointment in some quarters, the operation was a considerable improvement over the October 26 transit of the USS Lassen near Subi Reef in the Spratly Islands.

In the wake of the previous Freedom of Navigation Operation (FONOP), the administration’s top concern appeared to be to downplay the transit in order to prevent upsetting Beijing more than necessary. As a result, no U.S. officials would speak on the record about the operation for days, despite extensive coverage in every major media outlet. This left the door open for unattributed statements and speculation to fill the gap. As should have been expected, the result was significant confusion about what exactly the Lassen was objecting to with its FONOP. In reality, it took nearly two months before a U.S. official fully and publicly explained the operation and its intentions.

By contrast, the Department of Defense was ready with a statement on the Curtis Wilbur’s FONOP within hours. Not only did the Pentagon take control of the messaging so it could not spin out of control, as happened following the Lassen’s operation, but it did so with relative clarity. Where did the operation take place? “Within 12 nautical miles of Triton Island.” What did the destroyer do? “Transited in innocent passage.” What excessive maritime claim was it contesting? “Policies [of China, Taiwan, and Vietnam] that require prior permission or notification of transit within territorial seas.”

Equally important is that the planning of the recent FONOP seems to have been undertaken with the legal clarity and depoliticized nature typical of the Freedom of Navigation Program. Triton’s status as a legal rock or island (most likely the former) under international law is clear—it is above water at high tide and there are no nearby features whose maritime entitlements could complicate the undertaking or meaning of a FONOP. Subi Reef, by contrast, is a submerged feature that lies within 12 nautical miles of an unoccupied rock, which creates legal ambiguity about whether or not it bumps out the territorial sea of that rock and whether there is a legal requirement for innocent passage within 12 nautical miles of it.

The difference in clarity between the two operations is evident in the official explanations of their purposes. Compare the language of the Pentagon statement regarding the Curtis Wilbur’s transit to Defense Secretary Ashton Carter’s explanation of the Lassen’s operation:

Given the factual uncertainty, we conducted the FONOP in a manner that is lawful under all possible scenarios to preserve U.S. options should the factual ambiguities be resolved, disputes settled, and clarity on maritime claims reached. The specific excessive maritime claims challenged in this case are less important than the need to demonstrate that countries cannot restrict navigational rights and freedoms around islands and reclaimed features contrary to international law as reflected in the LOS Convention.

The secretary’s explanation of the legal uncertainties surrounding Subi Reef are accurate. But the more important question is left unanswered: Why perform a FONOP there at all? If the United States wanted to challenge restrictions placed by China on innocent passage, there are five Chinese-occupied features in the Spratly Islands that indisputably generate a territorial sea or bump out the territorial sea of a nearby feature. If it wanted to challenge the right of a feature to generate a territorial sea at all, then Mischief Reef is the only Chinese-occupied feature that indisputably does not have one. Instead Subi was presumably chosen, at least in part, because the legal ambiguity surrounding it would allow the administration to avoid explaining exactly what it was objecting to, thereby avoiding undue controversy.

Not only did that plan backfire, but it also forced the administration to rationalize the operation in a way that appears inconsistent with the goals of the FON Program. As Commander Jonathan Odom, who formerly had a hand in guiding the program, has explained, U.S. FONOPs are always undertaken with great legal deliberation, and their rationale explained as transparently as possible, to make clear precisely how and why the United States objects to specific excessive maritime claims.

Nevertheless, the recent FONOP has many upset that the administration is being overly-cautious. And admittedly, engaging in innocent passage without prior notification amounts to the low-hanging fruit of potential FONOPs in the South China Sea. Passing within 12 nautical miles of Mischief Reef while engaged in activities that are clearly not consistent with innocent passage and therefore asserting that the United States does not recognize a territorial sea from the formerly-submerged feature would cut to the heart of the matter. It would be a much more effective way to contest China’s attempts to restrict freedom of navigation near its artificial islands.

It was a let-down that the Pentagon directed this FONOP toward the Paracels instead of the Spratlys. And some might see it as a disappointment that it merely engaged in innocent passage instead of contesting other claims such as China’s illegal straight baselines around the Paracels. But for the FON Program to be effective, it must eventually contest any and all excessive maritime claims, and it must do so regularly and without becoming overly politicized. If the U.S. government is to follow through on its commitment to undertake FONOPs with increasing frequency in the South China Sea, then a wide range of operations will need to be undertaken, contesting the entire spectrum of excessive claims being made by China and other claimants in the South China Sea.

After the criticism it received in the wake of the Lassen’s operation, it should not be all that surprising that the administration looked to the less controversial end of that spectrum for its next FONOP. Compared to its predecessor, this operation was a success. And there will be plenty more FONOPs to come. But if another three months pass and China’s apparent claim of the right to restrict freedom of navigation based on artificial islands remains uncontested, then I will join the chorus of disappointment.

About Gregory Poling

Gregory B. Poling is senior fellow for Southeast Asia and director of the Asia Maritime Transparency Initiative at CSIS. He oversees research on U.S. foreign policy in the Asia Pacific, with a focus on the maritime domain and the countries of Southeast Asia. His research interests include the South China Sea disputes, democratization in Southeast Asia, and Asian multilateralism.