Arguments by Manila, Washington are flawed
Why the Philippines' unilateral initiation of the arbitration case violates international law
"Pacta sunt servanda" (Latin for "agreements must be kept") is a basic principle of international law. China and the Philippines previously reached agreement in bilateral documents on resolving disputes in the South China Sea through bilateral negotiation. Unilaterally initiating the arbitration case and ignoring the previous agreement violated international law.
The unilateral initiation of the arbitration case is a violation of the United Nations Convention on the Law of the Sea and an abuse of arbitral procedures provided for by UNCLOS. Given the fact that China and the Philippines made a clear choice on the means and procedures for settling their disputes, third-party settlement procedures provided for in UNCLOS do not apply.
Why the U.S. concept of "freedom of navigation and overflight" is wrong
There has never been any incident affecting freedom of navigation or overflight in the South China Sea, through which 16,000 vessels pass each year.
However, by playing up the issue, the United States is pursuing a hidden agenda.
By alleging that its massive military presence in the South China Sea is essential for freedom of navigation and overflight, the U.S. is attempting to take all the credit on the international stage for ensuring something that is not actually threatened.
The U.S. is portraying China's growing military strength as a major threat to freedom of navigation and overflight in the South China Sea and ratcheting up the bogus "China threat". The U.S. is creating an excuse to meddle in the South China Sea and bolster U.S. global strategy and maritime hegemony. Politically, the U.S. wants to create and hype up tension in the South China Sea. Militarily, it seeks legal ground for close-in reconnaissance activities.