|The famous "nine-dash line" that marks China's territorial claims in the South China Sea|
Source: "Q&A: South China Sea Disputes." BBC News. 15 May 2013.
Earlier this afternoon The House Committee on Foreign Affairs Subcommittee on Asia and the Pacific held a hearing devoted entitled "America’s Future in Asia: From Rebalancing to Managing Sovereignty Disputes." The key testimony was delivered by Daniel Russel, a career FSO currently serving as Assistant Secretary over the Bureau of East Asian and Pacific Affairs. Mr. Russel was one of the architects of the 'pivot to Asia' schema and has had extensive experience as an FSO in both Korea and Japan. Mr. Russel's testimony was a chance to explain in plain terms the Obama administration's policy towards territorial disputes in the East and South China Seas and spell out exactly "what [the State Department] mean[s] when the United States says that we take no position on competing claims to sovereignty over disputed land features in the East China and South China Seas." 
The Assistant Secretary's remarks are interesting. At seven pages they are a quick read (those pressed for time can skim the first two pages, for the most part diplomatic platitudes of the standard sort) that reveal a lot about the state of U.S. policy towards China and the various nations of maritime Asia. As if often the case with official government statements, the most striking aspect of Mr. Russel's testimony was not the things he said, but the things he did not. Mr. Russel's description of the State Department's line on the disputes in the South China Sea was detailed, lucid, and well thought out. His remarks on China's dispute with Japan over the Diaoyu/Senkaku islands was much more vague, uncertain, and brief.
Consider his description of the American position on the East China Sea disputes:
And in the East China Sea, we remain concerned about the serious downturn in China-Japan relations. We support Japan’s call for diplomacy and crisis management procedures in order to avoid a miscalculation or a dangerous incident. It is important to lower tensions, turn down the rhetoric, and exercise caution and restraint in this sensitive area. China and Japan are the world’s second and third largest economies and have a shared interest in a stable environment to facilitate economic growth. Neither these two important countries nor the global economy can afford an unintended clash that neither side seeks or wants. It is imperative that Japan and China use diplomatic means to manage this issue peacefully and set aside matters that can’t be resolved at this time.Now compare this with the length and detail of the State Department's position of the South China Sea disputes:
China’s announcement of an Air Defense Identification Zone (ADIZ) over the East China Sea in November was a provocative act and a serious step in the wrong direction. The Senkakus are under the administration of Japan and unilateral attempts to change the status quo raise tensions and do nothing under international law to strengthen territorial claims. The United States neither recognizes nor accepts China’s declared East China Sea ADIZ and has no intention of changing how we conduct operations in the region. China should not attempt to implement the ADIZ and should refrain from taking similar actions elsewhere in the region. 
There is a growing concern that this pattern of behavior in the South China Sea reflects an incremental effort by China to assert control over the area contained in the so-called “nine-dash line,” despite the objections of its neighbors and despite the lack of any explanation or apparent basis under international law regarding the scope of the claim itself. China’s lack of clarity with regard to its South China Sea claims has created uncertainty, insecurity and instability in the region. It limits the prospect for achieving a mutually agreeable resolution or equitable joint development arrangements among the claimants. I want to reinforce the point that under international law, maritime claims in the South China Sea must be derived from land features. Any use of the “nine dash line” by China to claim maritime rights not based on claimed land features would be inconsistent with international law. The international community would welcome China to clarify or adjust its nine-dash line claim to bring it in accordance with the international law of the sea.Other than a firm stand against the new Chinese ADIZ, the Assistant Secretary has nothing substantive to say about the Diaoyu/Senkaku dispute other than "China and Japan cannot afford an unintended clash." In contrast, Mr. Russel clearly articulates how the United States wants the territorial conflicts of the South China Sea resolved, both outlining the means through which he believes this goal can be attained and openly stating the steps the United States and other countries must take to make this vision a reality.
We support serious and sustained diplomacy between the claimants to address overlapping claims in a peaceful, non-coercive way. This can and should include bilateral as well as multilateral diplomatic dialogue among the claimants. But at the same time we fully support the right of claimants to exercise rights they may have to avail themselves of peaceful dispute settlement mechanisms. The Philippines chose to exercise such a right last year with the filing of an arbitration case under the Law of the Sea Convention.
Both legal and diplomatic processes will take time to play out. The effort to reach agreement on a China-ASEAN Code of Conduct has been painfully slow. However, there are important steps that the relevant parties can take in the short term to lower tensions and avoid escalation. One line of effort, as I mentioned earlier, is to put in place practical mechanisms to prevent incidents or manage them when they occur. Another common-sense measure would be for the claimants to agree not to undertake new unilateral attempts to change the status quo, defined as of the date of the signing of the 2002 Declaration of Conduct, that would include agreement not to assert administrative measures or controls in disputed areas. And as I have indicated, all claimants – not only China – should clarify their claims in terms of international law, including the law of the sea.
In the meantime, a strong diplomatic and military presence by the United States, including by strengthening and modernizing our alliances and continuing to build robust strategic partnerships, remains essential to maintain regional stability. This includes our efforts to promote best practices and good cooperation on all aspects of maritime security and bolster maritime domain awareness and our capacity building programs in Southeast Asia. 
This pattern is repeated throughout the testimony--time and again, the Assistant Secretary's position on the South China Sea is both clearer and more nuanced than his position on East Asian disputes. The South China Sea is given double the space. The words "Japan" or "East China Sea" are used 12 times in the testimony; the words "South China Sea" or "ASEAN" occur 21 times.
There are three possible reasons why the State Department discusses the South China Sea disputes with greater depth than the dispute in the East China Sea:
1) The Obama administration is more concerned with disputes in the South China Sea than the East China Sea.I suspect that the third option comes closest to the truth. The administration assumed that a declared 'pivot to Asia' would bring stability to East Asia. But as discussed here before Tokyo has only been emboldened by America's rhetorical support, and relations between China and America's most audacious ally have soured since.  Japan and China's dispute poses a problem that American statesmen do not know how to solve.
2) The Obama administration does not want its position on the Diaoyu/Senkaku dispute known publicly.
3) The Obama administration does not yet have a coherent position on the Diaoyu/Senkaku dispute.
 Daniel Russel. "Maritime Disputes in East Asia." Testimony to the House Committee on Foreign Affairs Subcommittee on Asia and the Pacific (5 February 2014). p. 6.
 Ibid. 4
 Ibid. 5-6.
 T. Greer. "Asian Geopolitics: Spring 2013." The Scholar's Stage. 19 May 2013.