The variance of views between China and the United States regarding the South China Sea situation is quite significant and stark. More worrying, both have publicly staked out positions that make it politically difficult to back down or even compromise.
What are the possible and most probable scenarios going forward?
'Leaking' status quo
The most likely scenario is a continuation of the status quo - even though it is "leaking". In this scenario, the US continues to challenge China's actions and sovereignty by overflying geographical features, and sailing warships within the features' presumed 12 nautical miles territorial sea. This would imply non-recognition of China's sovereignty and its prior-notification regime for warships to enter its territorial sea.
To avoid unnecessarily provoking and embarrassing China, the US may restrict these probes to only those features that were not above high water before the reclamation activities and are therefore not islands, according to the United Nations Convention on the Law of the Sea.
China does not respond physically to these provocations but does increase its warnings and verbal criticism of the US actions. Meanwhile, the US continues to strengthen its military alliances and "friendships" in the region, and the US and China both lobby intensely within Asean to gain support for their respective positions.
Relations deteriorate. If there is no compromise, eventually, a tipping point is reached and the two become open rivals, the region becomes polarised, a regional arms race ensues, and incidents become relatively frequent and dangerous.
The US may organise and lead "from behind" a major multilateral naval exercise in the South China Sea involving Australia, Japan, the Philippines and probably others.
The focus would be on civilian issues, like search and rescue, safety of navigation, natural disaster and humanitarian crisis response, and environmental conservation.
China argues that its reclamation is primarily designed to support such civilian-oriented activities, and has even invited the US and others to use the facilities "when conditions are right".
In this context, the participants might invite China to join the exercises. In any case, the multilateral activities would include overflight and vessel penetration of some features and their territorial sea.