The United States is one of the countries that helped shape the United Nations Convention on the Law of the Sea and its subsequent revisions, but as yet the US has still not signed it.

However, Secretary of State Hillary Clinton recently urged US legislators to approve the country's accession to the convention, saying that joining the convention would secure US navigational rights and its ability "to challenge other countries' behavior on the firmest and most persuasive legal footing, including in critical areas such as the South China Sea".

It is the US' global strategy adjustment that has prompted this change of heart. The US is rebalancing toward the Asia-Pacific region and cannot wait to interfere in the South China Sea disputes using the legal framework of the convention, especially as China and the Philippines are locked in a naval standoff near Huangyan Island. This is fully demonstrated by Clinton's remarks that the US is ceding the legal high ground to China and is not as strong an advocate for its friends and allies as it would like to be.

However, even if the US does finally ratify the convention, it will not become a concerned party in the South China Sea. It is not and never will be, as it is sovereignty disputes over islands in the South China Sea that are the issue and the US has no sovereignty claims.

The United Nations Convention on the Law of the Sea, with due regard for the sovereignty of all states, establishes "a legal order for the seas and oceans which will facilitate international communication, and will promote the peaceful uses of the seas and oceans, the equitable and efficient utilization of their resources, the conservation of their living resources, and the study, protection and preservation of the marine environment".

The convention, therefore, clarifies and regulates a country's maritime interests extending from established sovereignty. The convention per se plays no part in resolving disputes over sovereignty. Hence, the US and its allies in the region are doomed to fail in their attempt to dispute China's sovereignty and historical title over the islands in the South China Sea by manipulating the convention.

Besides the convention cannot be used to challenge China's sovereignty and historical title over the islands within the nine-dotted line, which was actually established long before the convention came into effect and conforms to intertemporal law. Chinese people discovered and named the islands more than 2,000 years ago and have exercised effective jurisdiction over them ever since.

Today, other claimant countries question the legitimacy of China's nine-dotted line in a bid to deny China's sovereignty over the islands and the surrounding waters. However, when China first announced the U-shaped line in the South China Sea in 1947, the international community did not oppose it, nor did any neighboring countries protest against it.

Another impetus for the US to join the convention is to justify its claim that freedom of navigation needs protecting in the South China Sea. China respects and protects freedom of navigation on the high seas in accordance with the convention and Chinese laws, however, the waters of the South China Sea are not the high seas. The US cannot enjoy absolute freedom of navigation in the South China Sea, as waters within the nine-dotted line are under China's jurisdiction and surrounding countries also claim their exclusive economic zones in this area. Freedom of navigation in the South China Sea is just another excuse used by the US to muddy the waters in the region and implement its "back to Asia" strategy.

Even if it ratifies the convention the US cannot conceal its strategic ambition and political calculation. The convention was opened for signatures in 1982, but the US refused to sign it insisting that part of the convention that concerns deep sea mining is against its interests. But, impelled by new interests, the US is now striving to become a signatory to the convention. The US should realize that once it becomes a signatory to the convention, it will have to deal with maritime affairs according to the rules and principles of the convention, which is likely to prove a challenge to the US.

Yet, even if the US becomes a party to the convention it will still be an outsider in the South China Sea.

The author is a professor of international laws at Southwest University of Political Science and Law in Chongqing.