|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).
I'll focus here on their most important point of dispute: the nature of America's interests in the South China Sea. I am consistently amazed at how little this is discussed in American circles. The republic's interests in the territorial squabbles of the region are assumed, not argued over. How Chinese machinations in the sea should be stopped is often debated--why America should bother with the stopping never is. This is unconscionable. China's pressing interests in the South China Sea are natural and obvious. Those of the United States, a country an ocean away, are remarkably less so. The failure of American statesmen to articulate a convincing explanation for U.S. involvement in these disputes lies at the root of both Chinese mistrust of American intentions and the fears of American allies that Washington is not truly committed to their security. Above all else, American citizens and servicemen deserve an explanation for why they should care about a few god-forsaken atolls thousands of miles from their home.
I am thus quite grateful that Goldstein forces this conversation upon us. He does so by arguing that Americans really shouldn't care about the islands after all:
The notion persists that U.S. national interests amount simply to the aggregate of interests of all allies and partners. Thus, as Beijing has often complained, Washington’s eagerness to please and to allay all concerns has created perverse incentives for allies and partners to press for maximalist positions within various disputes with the hope that Uncle Sam will have their backs if push comes to shove. In a risk/reward matrix, some Philippine nationalists could come to the seemingly far-fetched conclusion that it is really worth it for Manila to risk World War III in order to secure drilling rights on Reed Bank. The Philippines would likely suffer enormously in such a conflict, of course, and very few Americans would try to make a similar case. Indeed, the example shows how Philippine and American interests could logically go in quite separate directions. One might even say that Manila enters a zone of serious moral hazard in hoping that Washington would take such risks for the sake of just another oil patch. It turns out the major diplomatic error has been to give The Philippines the wrong-headed idea that the U.S. would actually entertain such grave risks. Alternatively, the alliance could be much strengthened if it remained grounded within the scope of common sense. That is to say that the U.S. defense commitment to the Philippines should be defensive in orientation and cover the main islands, including Palawan, Luzon, etc, but no ill-defined and unexplored “grey zone” claims. Why the U.S. should entertain any conflict, let alone major hostilities, with China over maritime disputes with U.S. “partner” Vietnam is completely mystifying. He continues:
One of the most common, but silliest ideas floating about on the South China Sea is that the area’s economic dynamism implies that the U.S. must maintain unchallenged military supremacy in these waters. Taken to a bizarre extreme, this logic even claims that the entire global trading system (the “rule-based order”) is under grave threat from Chinese actions in the South China Sea. In short, stand up to China or watch the global economy come crashing down. Good luck finding a credentialed economist or even a Wall Street analyst, who would agree with this assessment. What makes this line of argumentation so specious, of course, is that China has been the major driver for this region’s extraordinary economic dynamism. The argument that maritime trade (and with it the global economy) will crash if China gains additional strategic influence in the South China Sea is, at best, a 19th century anachronism in our collective discourse. At worst, it is simply foolish drivel that makes for fine-sounding political rhetoric. Washington would be better served taking a page from Beijing’s playbook and attempting to turn its own backyard into a dynamic force in the global economy. The U.S.-Cuba rapprochement is a hopeful start towards such a project. 
The bolded emphasis is my own. I've also taken the liberty to bold the best sections of Alexander Vuving's response:
...The risk of a direct conflict between Washington and Beijing exists even without U.S. support for its allies and partners in the region. The territorial dispute in the South China Sea represents just the tip of the iceberg; buried under the surface is a more strategic competition for supremacy in the Western Pacific. China and the United States are the two major contestants in this competition, though other nations including Japan, the Philippines, Vietnam and India also have significant roles to play.
Having no permanent presence in the South China Sea and with a home base far away, the United States has to rely on Vietnam, the Philippines and to a lesser extent Malaysia to keep the regional balance of power from tilting too far in favor of China. In this regard, American and Southeast Asian interests are complementary rather than conflicting. Helping allies and partners is also an economic way to serve U.S. interests in the region. The real question here is not whether, but how America should support its allies and partners in the South China Sea. There are multiple options to consider in addressing this question, and a direct Sino-American conflict is a risk to prevent, not a logical consequence of U.S. support for allies and partners in conflict with China.
But why must the United States compete for supremacy in the Western Pacific? The near-standard answer is that America has a national interest in freedom of navigation and U.S. military supremacy in these waters is the best guarantee for that. I think this answer has flaws, but not for the reasons offered by Goldstein. First, although the United States has an important interest in the South China Sea, freedom of navigation is not the best term for this interest. Second, there is another reason for the United States to compete for supremacy in the Western Pacific. Let me explain.
The term “freedom of navigation” is a bad choice of words. Its meaning varies according to the legal position or the national perspective you take. What is at stake here is not so much freedom of navigation as an actual situation, but the right of free access to the waters and skies in this crowded area. There is a crucial difference between Chinese and U.S. commitments to “freedom of navigation” in the South China Sea. This difference stems from the fundamental fact that while the United States upholds the notion of the global commons, China cherishes the idea of the “nine-dash line.” With this idea, Beijing considers the domain indicated by the “nine-dash line” as something like a sovereign realm it has lost to others and it is entitled to get back. China and the United States may share the same view when it comes to nautical freedom in most maritime areas on earth, but the South China Sea is a special case because of the “nine-dash line.” While Washington acknowledges the right of everyone, even its enemies, to freely access the waters and skies in this region, Beijing reserves the right to itself. When China says it guarantees freedom of navigation in the South China Sea, the tacit understanding is that as a benevolent power, it opens its gates to everybody, but others must respect its sovereignty.
China is far from being able to control all the “gates” along the “nine-dash line,” and even if it can do so, it will not close these “gates.” After all, China has an enormous vested interest in keeping the flow of commerce through the South China Sea unimpeded. The threat posed by China to freedom of navigation and overflight in this area affects the normative basis of this freedom more than the practical situation. If the Chinese Navy becomes the custodian of nautical freedom in these waters, most vessels, most of the time, can still sail through them unhindered, but that is not because nations enjoy the objective right of free access, but because they enjoy China’s subjective benevolence, which at times can be selective and arbitrary. This subtle detail may not be important for insurance and shipping companies, but it will have far-reaching consequences for world politics. It means that in the regional order underwritten by China international law must yield to Chinese policy.
Even if China will behave the same as the United States does, Chinese supremacy in the East and South China Seas will still pose a grave threat to U.S. leadership in the region. The concentration in this domain of Asia’s chief arteries means that, to paraphrase Harold Mackinder, he who controls the East and South China Seas, dominates Asia; and with the rise of Asia, he who dominates this region, commands the world. For seventy years since the last days of World War II, U.S. naval supremacy in the Western Pacific has enabled Washington to play a leadership role in Asia. For its part, China has increasingly exhibited the conviction that its road to Asian primacy also runs through supremacy in these waters. The debate is worth reading in full. Vuving's distinction between American and Chinese conceptions of "freedom of navigation," in particular, should be remembered in all of discussions of Chinese claims in both the South and the East China Seas. But in some ways the terms of this debate were painfully limited. Like most editorials and policy memos written on the South China Sea, the essays in this debate dissect American policy in the South China Sea without reference to the larger context in which American policy is made.
The South China Sea is not the only crisis zone on Washington's radar. For every opinion piece urging Washington to take the South China Sea more seriously, there is one lamenting the failure of American resolve in Afghanistan, another exhorting the United States to show greater commitment to our allies in Eastern Europe, and two more pushing for a larger American role in the fight against ISIS. The United States needs to shore up its prestige just about everywhere.
This is not possible. We live in a sequester era. Americans are sick of foreign entanglements, Congress is a dysfunctional mess, and budget cuts are sweeping across the services. The United States simply cannot be everything to everyone. We have to choose what battles are most important to win--and by extension, what battles can be lost and forgotten. The question is not "are the territorial disputes in the South China Sea vital to American interests?" but "are the territorial disputes in the South China Sea more vital to American interests than what is happening in Syria, Ukraine, North Korea, and other crisis zones across the globe?" 
Americans are always uncomfortable when I state the problem this way, but this is a reality we have to face. To strategize is to prioritize. To argue for active American involvement in the South China Sea is to argue that other regions, problems, and commitments should receive less attention from Washington. Those who want the United States to step up in the South China Sea must recognize that this means stepping down somewhere else. It is far past time for those who argue thus to justify why the South China Sea should take priority over America's other commitments.
Other posts from the Scholar's Stage about the South China Sea:
"The CNRP Won't Save the South China Sea"
T. Greer. The Scholar's Stage (3 July 2015).
"A Few Comments on China, Vietnam, and the HYSY981 Crisis"
T. Greer. The Scholar's Stage (22 May 2014).
 Lyle Goldstein "The South China Sea Showdown: 5 Dangerous Myths," National Interest (29 Septemeber 2015); Alexander Vuving, "Think Again: Myths and Myopia about the South China Sea," National Interest (16 Octoeber 2015).
 Goldstein, "South China Sea Showdown,"
 Vuving, "Think Again,"
 Of course, this same question can--and should--be addressed to those who are arguing for an expanded role for U.S. forces in Eastern Europe, the Near East, Afghanistan, and so forth. I made this point explicitly in reference to the Near East in the post "Iran: The Debate We Should Be Having" Scholar's Stage (24 July 2015).