The travel/adventure writer Robert Young Pelton is not the first person that would come to most minds when asked to name an expert on global politics and international affairs. He is an entertaining writer with a large supply of war correspondent / stringer / freelance journalist "So there I was, in the middle of the chaos" anecdotes. His books are readable and fun, occasionally informative. That said, he really deserves some credit for writing as early as the mid to late 1990s that the South China Sea was going to be a key axis of international conflict in the early 21st Century. Seriously. This guy was writing about the Spratly Islands, the Paracel Islands, and Scarborough Shoal back when the rest of the world was still in the mindset of the Cold War or sagely explaining that India and Pakistan seem not to like one another very much. Pelton has made me sound prescient more than once for being able to cite the conflict over rock and coral clumps in the South China Sea long before the international press started bandying about terms like "Great Wall of Sand" and The Nine-Dash Line over the past year or two. Simon Winchester was also ahead of the game on this one, as were (I'm sure) many Asian experts whose writing is not widely available in this hemisphere. Searching "South China Sea" on Amazon shows a dozen nonfiction books on the topic written in 2014, 2015 or 2016. It's pretty impressive that some people were 20 years ahead of the game on it.
The Japan Times has a good Scarborough Shoal piece today, and other than to give Pelton some props I don't think I can explain the conflict any better than I could inform you by sharing some useful writing on the subject. Long story short: China and a number of others in the region – Taiwan, the Philippines, Singapore, Malaysia, Vietnam, and others – assert historical ownership of a number of tiny, uninhabited rocks that were of no interest to anyone until modern times. They contain no resources, which one might expect, but they are outposts for establishing Exclusive Economic Zones and national-military sovereignty in an economically and strategically vital area of the world. China's approach has been one of extreme belligerence, building artificial islands (hence "Great Wall of Sand", referring to landfill) around rocks barely big enough to stand upon and staging military personnel and equipment there. Shipping lanes, fishing areas, potential undersea oil resources, and the patrol lanes of international navies (particularly the US Navy) are all affected by the outcome of this strategic land-grab.
One interesting thing I can add is that all of this has been made possible in part by a volcano. True story. When Mount Pinatubo erupted in 1991 in the Philippines – the largest eruption of the 20th Century, incidentally, which not many non-Asians realize – the US closed Clark Air Base and Subic Bay Naval Base. Both were heavily damaged and in the post-Cold War mindset of the 90s, once evacuated the decision was made not to return to either. The US withdrawal from the region left a power vacuum that the Chinese armed forces were more than eager to fill. In March of 2016 the Philippine government cordially invited the US military to place personnel and equipment at 5 bases in the region, a result of Obama's "Asian Pivot" strategy.
Thanks for helping me sound like I know what I'm talking about sometimes, RYP.