Freedom to Navigate - "Freedom of Navigation Operations" as challenges to "excessive claims to water and airspace"

Interesting read at Foreign Affairs "All in Good FON: Why Freedom of Navigation Is Business as Usual in the South China Sea" by Mira Rapp-Hooper (a reprint of an Oct 2105 article):

Rumors first emerged in May 2015 that the Pentagon was contemplating military operations around China’s new artificial islands among the Spratly Islands. Through such exercises, the United States would aim to demonstrate that it does not recognize spurious Chinese claims to water and airspace around the islands.
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As the history of the Freedom of Navigation Program and its relationship to international law make clear, however, such operations would complement U.S. diplomacy and, although they would contest China’s claims to water and airspace under the UN Convention on the Law of the Sea (UNCLOS), they would not contest its claims to territory.
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In a recent Senate hearing, Senator John McCain (R-Ariz.) argued that Washington’s failure to transit within 12 nautical miles of China’s claims “grants de facto recognition” of them. A report soon followed with the headline “McCain: U.S. Should Ignore China’s Claims in South China Sea.” This was likely not the message the Senator intended to convey, but reporting has consistently suggested that FONOPS would be used to push back against China’s claims to territory. The United States, however, has a long-standing policy that it does not take a position on other countries’ sovereignty disputes. FONOPS are meant to challenge excessive claims to water and airspace; they do not challenge territorial claims.

In other words, the FONOPS reality is both considerably more nuanced and far less escalatory than the popular narrative suggests. (emphasis added)

Yes, very nuanced. But:

. . . [P]recisely because the South China Sea territories are disputed, and because Washington does not take a position on such sovereignty disputes, it need not recognize territorial seas or airspace around any of China’s artificial features—or those of any other countries. In short, territorial seas are a function of recognized state sovereignty, and where that sovereignty is disputed, vessels and aircraft may pass freely.

... even if China’s Spratly holdings were uncontested, the fact remains that Beijing’s seven island features are artificial. Under UNCLOS, man-made islands do not confer territorial seas or airspace. Rather, they are granted only a 500-meter safety zone. In China’s case, before its building spree, at least three of its seven artificial islands were low-tide elevations or reefs, rather than rocks or islands. Under international law, these features are not even subject to sovereignty claims—by China, or by anyone else. By this logic, even without persistent sovereignty disputes, Mischief Reef, Gaven Reef, and Subi Reef would not be entitled to water or airspace of their own, and therefore may be especially appropriate features around which to transit.

Since the Chinese aren't being all that subtle - in that they are making very territorial-like claims, nuance may be wasted.

Who is willing to go to war to keep the South China Sea open to free navigation?

Or for that matter, who is willing to fight to close the South China Sea to the free passage of ships under international law?