This week as the world watched with baited breath the American presidential election the last thing that most people were thinking about was sea and oceans. Yet both George W. Bush and John Kerry were unanimous on one important point of foreign policy — although neither spoke a word about it. They agreed, if elected, that they would move to ratify the UN’s Law of the Sea. It could happen before the month is out.

All the road blocks of the last twenty years since President Reagan decided to torpedo the treaty have been removed and Congress is poised to give the White House the green light on ratification. It will be a momentous step forward for international law, one which defeated a willing Bill Clinton and is out of character for the unilateralist-inclined George W. Bush. But the consensus in Washington is now very real.

Until the Law of the Sea was drafted the seas and oceans around us, two thirds of our planet, were largely lawless.

When 350 years ago the Dutch jurist, Hugo Grotius, formulated the doctrine of the freedom of the seas, laissez faire seemed a magnificent idea. “Let no man possess what belongs to every man.”

But this is the age of giant tankers, oil spills that destroy whole coasts, declining fish catches, disputes over rights of passage and maybe the beginnings of a gold rush for minerals and genetic resources on the bottom of the sea.

After 26 years of negotiation in which America played an active part the Law of the Sea came into force ten years ago this month. It was an historical milestone in the annals of nation state competition and commercial exploration. It gave the world a chance to arrange for mankind a fair distribution of its common patrimony of the seas.

It has the chance of establishing precedents that could be applied to other endeavors like the slicing up of oil-rich Antarctica and Artic Ocean, currently being disputed by nations as diverse as Denmark and Russia, the future frontiers of the Moon, the planets and outer space. This is why some say it is, in its own way, a Magna Carta for the 21st century.

It was a Republican president, Richard Nixon, who first coined the term to describe the seas as “the common heritage of mankind”. Nixon’s attitude was anomalous: The US attitude to international law had long been ambiguous and uncertain.

President Harry Truman was the first to challenge the conventional wisdom then reigning as laid down by Grotius. In 1945 he proclaimed US jurisdiction over the seabed resources of the continental shelf.

Three years later, Chile, Peru and Ecuador raised the stakes by claiming 20-mile maritime zones and seizing American tuna boats fishing in their waters. The fear was that nations might go further and declare exclusive 200-mile territorial waters.

It was in an attempt to find some accommodation among these new coastal jurisdictions and traditional high seas freedom that the Law of the Sea conference was convened. The result was one of the great negotiating texts of all time — far more comprehensive, detailed and demanding of shared sovereignty than that for the International Criminal Court. It weighs the interests of continental nations like the US and Russia, islands like the Philippines and Jamaica and landlocked states such as Austria and Chad.

The treaty rolls back existing claims of territorial jurisdiction wider than 12 miles. It writes into international law the right to free and unimpeded passage through the 100 straits that are narrower than 24 miles. (This has brought the Pentagon down firmly on the side of the treaty after a series of disputes including one with good neighbor, Canada, over the North West Passage, now steadily becoming ice-free.) And the treaty while recognizing exclusive 200-mile economic zones for coastal states would not allow them to restrict the passage of ships or the overflight of planes of other nations.

Once the US ratifies the treaty the pressure will be on the few other dissenting states to ratify.

China, despite its nervousness about recognizing a treaty that would give the US Navy the undisputed right to patrol the Taiwan Strait, has long ago ratified it.

More the pity that the Law of the Sea does not address territorial disputes that were underway before it was negotiated — like who controls the Spratly Islands that pits China against Vietnam, Taiwan, and the Philippines. Future amendments of the treaty could deal with that. But America needs to ratify the treaty this month — the ten-year deadline is up — if it is to be eligible to vote on amendments.