The 1958 and 1960 United Nations conferences were of a piece, with the second convened to settle the unresolved questions from the first: the breadth of the territorial sea and fishing limits. At the earlier conference, the maritime powers had been preoccupied with disputes among themselves, but by 1960 they were forced to meet the challenges presented by states from the global South. Delegates from the latter took the view that the old maritime system upheld a discredited imperialist order, and they sought to bend the law of the sea to their own ends. Their campaigns to regulate the passage of warships through the territorial sea and to claim exclusive fishing zones and preferential fishing rights gave rise to disagreements with the powers, who sought to maximise the scope of their own naval and fishing operations. These differences would lead to the breakdown of the conference.

In the late 1940s, the Americans and the British made unilateral claims to continental shelves and fishing conservation zones, but tried to apply the brakes to further claims when other countries followed suit. The International Law Commission was given the task of producing draft articles to guide negotiations over a single law of the sea convention, which, they hoped, would rein in future claims. A conference was convened in 1958 under the auspices of the United Nations, at which the essential question, preceding all others, was the breadth of the territorial sea – ‘the base of the pyramid’, one delegate said – on which all other claims stood. Novel concepts were also addressed, such as the continental shelf and the exploitability criterion, the existence of a ‘genuine link’ between ship and state, and the abstention policy relating to high seas fishing. The conference drafted what would become five separate conventions, on the territorial sea and contiguous zone, the high seas, high seas fishing, the continental shelf, plus a protocol on dispute settlement. Yet in the end it failed, as had its predecessor in 1930, to settle the breadth of the territorial sea.