WASHINGTON • Whatever ruling is made by the Permanent Court of Arbitration, the United States will likely emphasise that all sides respect the verdict.
Experts say that though the US is hoping for a favourable decision - one that does not validate the nine-dash line - it is of greater importance that China does not upend established international norms.
"I think the main message the US is going to want to make clear is that we see it as legally binding on both parties," said Dr Amy Searight, former US deputy assistant secretary of defence for South and South-east Asia.
She added that if the Hague ruling does produce a positive outcome for the US, it may want to drive the point home by perhaps conducting freedom of navigation operations in the region to highlight the decision.
Officially, the US administration has said little since the date of the ruling was announced, but Asia watchers say the government should be prepared for how China might respond to a verdict it does not like.
Centre for Strategic and International Studies senior adviser Andrew Shearer said: "It will be a litmus test in the region of US consistency and resolve, and how it is going to deal with these problems."
Experts in Washington say a positive outcome should prompt the US administration to ratify the UN Convention on the Law of the Sea, to remove an argument China might use to ignore the ruling.
Jeremy Au Yong