Secretary of Defense Ash Carter’s address at this weekend’s Shangri-La Dialogue was generally well received by conference attendees and Asia-security watchers. A few critics have argued that Carter was “just talk.” What none have noted, however, is the fact that the Secretary’s remarks were the latest installation in a series of moves by the administration to articulate a fact-based approach to the South China Sea. This approach is a nuanced one and does not necessarily constitute a “strategy” for countering China’s recent moves. It is, however, a wise way to engage two key audiences to whom Carter was speaking at Shangri-La: other states in the region and China itself. Let me explain.

Until several weeks ago, the general public knew almost nothing about China’s island building efforts in the South China Sea. Major media outlets like the New York Times and the Washington Post began to cover Beijing’s island building in April, when China had already been dredging for over a year. This is not entirely surprising: Spratly land reclamation is an esoteric topic even for the well-informed foreign policy observer. Moreover, the United States itself does not have claims in the South China Sea. Washington absolutely has core articulated interests, such as the security of its allies, the peaceful resolution of disputes, and freedom of navigation, but it is not easy to explain to the international community or to the American people how exactly these are jeopardized by piles of sand and dozens of dredgers. Maps and imagery can help to make these activities more tangible, but they still have to be connected to policy goals.

Enter the facts. In early May, U.S. officials stated that they believed that China had reclaimed 2,000 acres of new land in the Spratly Islands over the course of 18 months. This was the first official estimate of the scale of Beijing’s projects. They also acknowledged for the first time that other claimants had engaged in recent island building, and noted that Vietnam’s projects comprised just 60 acres of new land over several years. This acknowledgment was important because it made clear that the scope of China’s activities, rather than land reclamation as a technique, was Washington’s worry. It also lent credibility to the contention that China’s island building was unprecedented in speed and scale.

The next big, fact-based move was the Pentagon’s decision to allow a CNN reporter to join a P-8 surveillance flight over the Spratlys and to declassify the video. The video included stunning footage of Fiery Cross, Mischief, and Subi Reefs. These artificial islands looked much like they do in satellite photos, but the video captured dregders in motion and construction under way, and in so doing conveyed the dynamism of China’s work. More importantly, it also captured several warnings by Chinese military personnel to the U.S. aircraft to leave the “military zone” it was approaching; the U.S. pilot responded that he was in international airspace and in compliance with international law. In this exchange, the Pentagon and CNN made palpable the most serious danger in the current Spratly standoff. Other states do not know what China believes its rights to be around its new outposts. And while many (including the United States) believe that China cannot claim sovereign territory, maritime entitlements, or national airspace based on this building, a major accident could occur if China behaves otherwise. This video clip communicated the national security stakes in the South China Sea better than any official pronouncement could.

The South China Sea portion of Carter’s Shangri-La speech tracked with remarks the Secretary made at the PACOM change-of-command ceremony in Honolulu two days prior. When speaking to the international Shangri-La audience, however, Carter did not simply rebuke China’s actions—he built his criticism on facts. His Shangri-La speech repeated the estimate that China had built 2,000 acres of new land in 18 months, and noted that international concerns came from uncertainty about Beijing’s intentions. Carter listed the number of outposts that each South China Sea claimant holds in the Spratly Islands, and acknowledged that others had built on their islands too. He called for a halt on land reclamation by all claimants, including China, and will reportedly raise the issue with Vietnam directly. And while reiterating the United States’ longstanding list of interest in the South China Sea, he also invoked international law to articulate Washington’s present and most pressing concern: “After all, turning an underwater rock into an airfield simply does not afford the rights of sovereignty or permit restrictions on international air or maritime transit.” So why all the facts when the world was watching?

The Pentagon and the administration are well aware that they need regional buy-in to implement any new ideas in the South China Sea. Precisely because the United States does not have claims in these waters but seeks to protect lofty principles, any Washington-led policy necessarily requires support from allies and partners. Countries in South East Asia are keenly aware that there are decades of history behind these disputes. They know that other claimants besides China have built up and reclaimed land features and even built airstrips. Moreover, many countries in the region are wary of being put in a position in which they are forced to choose between the United States and China. A fact-based assessment allowed states like Malaysia to express their deep concerns about China’s activities, while still acknowledging that the situation is complicated. A unilateral rebuke would have been counterproductive.

Another audience for Carter’s speech was, of course, China itself. The fact-based approach allowed the Secretary to be critical of Beijing without provoking ire. The South China Sea section of his speech was nested in a broader edifice of reassurance: the theme, after all, was that all states in the region should be able to rise if they do so peacefully. Carter also included mention of the two CBMS the United States and China signed in late 2014, and noted that the two planned to complete the air-to-air encounters annex later this year. China’s Ministry of Foreign Affairs issued a six-point retort to Carter’s statement that its island building is “out of step” with international rules,  but many members of the Chinese delegation said that they found Carter’s tone to be “acceptable.”  These delegates were presumably prepared to barrage the Secretary with accusations of “hegemonism” and “zero sum” thinking, but they had relatively few opportunities to use them. Unlike last year’s conference, U.S.-China plenary exchanges did not escalate the tensions of the last several weeks.

This is not to say that Carter’s facts charted the way forward in the South China Sea. There is a good deal more work to be done, including when it comes to the way the United States deploys information about this and other regional disputes. Carter took a strong stand on freedom of navigation, declaring: “The United States will fly, sail, and operate wherever international law allows, as U.S. force do all over the world. America, alongside its allies and partners in the regional architecture, will not be deterred from exercising these rights—the rights of all nations.”  As my colleague Bonnie Glaser has noted, however, Carter didn’t connect the dots to explain clearly that the United States fears that China may already be using its artificial islands to interfere with these rights. The P-8 video demonstrated that freedom of navigation and overflight in the South China Sea may already be contested. Yet Chinese officials insist that China has never interfered with freedom of navigation, and that this is a spurious concern. The PLA’s Senior Colonel Xiaozhuo Zhao did so at Shangri-La and did not meet with much resistance.

If the United States want to sustain international momentum on this issue it should catalogue instances in which it believes freedom of navigation has been threatened and make this data public. It should also scale up this transparent approach and apply it to the region as a whole. If the Pentagon’s $425 million Southeast Asia Maritime Security Initiative is funded, an early priority should be spending some of those dollars on partner maritime domain awareness capabilities. This would help to reduce the risk of accidents in the South China Sea, and would mean that the United States is not the sole provider of facts. Washington’s narrative will be stronger if it is supported by other regional voices.

It is also, of course, the case that a nuanced narrative is not a master strategy. There is evidence to suggest that the PLA does not believe that the United States will take a harder line on its South China Sea pursuits any time soon. Carter’s speech will only be an unqualified success if it lays the groundwork for bigger things to come.

We at the Asia Maritime Transparency Initiative are big fans of fact-based approaches. They are particularly important in the maritime domain, where events at sea can be particularly difficult to monitor. Transparency in the U.S.-China relationship may be easier said than done, however. As the dominant power that has helped to write many of the rules in the international system, the United States has ample incentive to be forthcoming about its actions and intentions. As a rising power that is rapidly gaining strength, China believes it has reason to play a closer hand. China may continue to try to create facts on the ground, but if the United States and others in the region continue to collect and publish data on the security situations, these won’t constitute fait accomplis. Transparency alone certainly will not solve the sovereignty disputes in the South China Sea, but it can help to manage them.

About Mira Rapp-Hooper

Dr. Mira Rapp-Hooper is a senior fellow in the Asia-Pacific Security Program at the Center for a New American Security. She was previously director of the Asia Maritime Transparency Initiative and a fellow in the Asia Program at CSIS