Indeed a court ruling would mean little if nobody is willing to back it up with the treat of military and/or economic action. So it would completely deepened whether or not Beijing beliefs there will be serious consequences come from not following the court verdict.
Major problem is that China is a major creditor for the US government. And considering that Obama threatened a veto over the 9/11 lawsuit bill, potentially out of fear that Saudi-Arabia might dump it US-bonds on the market and stop asking dollars for its oil, one could only imagine what might happen if China made a similar treat.
Combine this both India and Russia are forging closer (economic) ties with the country, including working together to create an alternative for the US-dominated IMF. Which would further complicate both trade embargo's and (hopefully) limited military action.
Of course this not the only territorial issue that involves China. There is the dispute with Japan. And of course the leftover of their civil war, Taiwan.
I fear this might require someone of the diplomatic talent of Bismarck or Kissinger to resolve the issue peacefully. And I do not see how one can successfully take on China without pulling a Nixon, but this time reaching out to Russia and/or India.