Everything Everywhere Daily

Episode: The Law of the Sea (Encore)

Host: Gary Arndt
Date: September 27, 2025

Overview

In this encore episode, Gary Arndt explores the fascinating development of the "law of the sea"—the system of international agreements and traditions that governs how countries use and control the world's oceans. Moving from ancient custom to modern treaties, Arndt explains how maritime law evolved, why international waters exist, who controls them (and how far out that control goes), and the significance of these laws in our modern, interconnected world.

Key Discussion Points and Insights

1. Origins: Early Customs on the High Seas

• Anarchy on the Seas: Early sailors operated without rules, in contrast to the more regulated land-based societies ([03:10]).
• Maritime Traditions: Over time, sailors developed their own customs and unwritten rules for navigation and dispute resolution ([03:45]).
• Notably Absent Romans: Despite Rome’s dominance around the Mediterranean, they did not create a formal code for the high seas, only basic shipping and insurance rules ([04:10]).

2. Early Maritime Law

• Rhodian Sea Laws (Byzantine Empire, ca. 800): The first known attempt to explicitly codify maritime laws, referenced in other texts but with no surviving original documents ([04:35]).
• Trani’s Ordinamenta et Consututo Maris (1063): Earliest surviving maritime law, setting frameworks for trade and dispute resolution ([05:15]).
• Other Medieval Laws: Additional rules like the Laws of Wisby and Rolls of Oleron focused on ships and shipping—not the sea itself ([05:50]).

3. The Age of Discovery and Claims to the Sea

• Treaty of Tordesillas (1494): Spain and Portugal divided the world’s new territories—“This treaty would have been great if you were Spain or Portugal. However, absolutely everybody else... had no incentive to honor the division...”
• Mare Liberum vs. Mare Clausum Debate:
  • Mare Liberum (“the free sea”) by Hugo Grotius (1609): Seas belong to no one; all nations have right of ‘innocent passage’. “You had the right of what was called innocent passage. And here I should explain what innocent passage is, because it's still a fundamental pillar of international law today.” ([07:45])
  • John Selden's Mare Clausum (1635): Seas can be claimed and controlled, especially near one’s coast—prompted by England's dislike of Dutch competition ([08:30]).
  • Cornelius van Bynkershoek (1709): Proposed sea territory should extend as far as a nation could defend (i.e., cannon shot distance, about 3 nautical miles) ([09:10]).

4. The Three-Mile Rule and Its Evolution

• Cannon Shot Rule: “This position... became known as the three mile rule. Under this rule, any coastal waters within three nautical miles...were considered the sovereign territory...This also became known as the cannon shot rule due to how simple and intuitive it was.” ([10:10])
• Exceptions: Special cases for straits, e.g., Magellan and Malacca, where passage close to land is unavoidable ([10:55]).

5. 20th Century Developments and Complications

• Post-War Changes:
  • Advancements in weaponry made the cannon shot rule obsolete.
  • Offshore resources—oil, minerals, fishing—led nations to claim greater control ([12:20]).
  • Environmental, economic, and security concerns demanded clearer legal frameworks.

6. The United Nations and Modern Law of the Sea

• League of Nations’ Failure: Pre-WWII attempts at regulation stalled ([13:10]).
• United Nations Conferences:
  • First (1958), Second (1960): Initial treaties signed ([13:40]).
  • Third Conference (1973-1982): Led to the United Nations Convention on the Law of the Sea (UNCLOS), the prevailing global treaty ([14:00]).
  • Entered into force in 1994 after ratification by 60 countries; now includes 168 signatories plus the EU ([14:40]).

7. UNCLOS: Defining Maritime Zones

• Territorial Sea (12 nautical miles): Country enjoys full sovereignty ([15:05]).
• Contiguous Zone (24 nautical miles): Country may enforce customs, immigration, and pollution laws ([15:45]).
• Exclusive Economic Zone (EEZ, 200 nautical miles): Sole rights to resources like fish, oil, minerals ([16:15]).
• Fundamental Principle: “Freedom of the seas allows for the previously mentioned innocent passage through territorial waters. Innocent passage applies to all vessels, including warships.” ([17:05])

8. Disputes and Non-Signatories

• Interpretation Issues: Disputes over ‘innocent passage’ have provoked international incidents—especially during the Cold War ([17:35]).
• Non-Ratifying Countries: Most are landlocked, but exceptions include Turkey, Syria, Venezuela, Peru, and notably, the United States.
  • US and UNCLOS: “The US has never ratified the Law of the Sea Convention. For 40 years, it has been rejected by multiple presidential administrations and Congresses, which have been controlled by both parties.” ([18:05])
  • Main objection involves international control over economic resources; however, the US largely adheres to the convention in practice ([18:40]).

Notable Quotes & Memorable Moments

• On the Absence of Roman Maritime Law

  “In the case of maritime law, that is not the case at all, which is actually rather odd. The Romans… never developed any explicit set of laws regarding the high seas.”
  — Gary Arndt, [04:10]

• On the Problem with Treaty of Tordesillas

  “This treaty would have been great if you were Spain or Portugal. However, absolutely everybody else in the world had no incentive to honor the division of the world…”
  — Gary Arndt, [06:25]

• Explaining Innocent Passage

  “Innocent passage is nothing more than the ability to sail from one point to the next without doing anything else. It does not include fishing, stopping, firing weapons, gathering data, conducting surveys, or anything.”
  — Gary Arndt, [07:55]

• On the Three-Mile Rule

  “This just coincidentally is about the same approximate distance that an adult can see to the horizon when standing on the shore. This position… became known as the three mile rule… also became known as the cannon shot rule due to how simple and intuitive it was.”
  — Gary Arndt, [10:10]

• On US Non-Participation in UNCLOS

  “The US has never ratified the Law of the Sea Convention… despite not having ratified the treaty, the US does de facto adhere to almost everything else in the treaty. They just haven’t formally ratified it.”
  — Gary Arndt, [18:05-18:40]

Important Timestamps

• 03:45 – Early maritime customs and traditions
• 04:35 – Rhodian Sea Laws and medieval beginnings
• 06:25 – Treaty of Tordesillas and global division
• 07:45 – Hugo Grotius’s ‘Mare Liberum’ and concept of innocent passage
• 10:10 – The three-mile (cannon shot) rule
• 13:10 – League of Nations pre-WWII efforts
• 14:00 – United Nations Convention on the Law of the Sea formation
• 15:05 – Territorial sea, contiguous zone, and EEZ explained
• 18:05 – US non-ratification of UNCLOS

Conclusion

Gary Arndt’s episode skillfully traces how centuries of debate, conflict, and diplomacy forged today's maritime laws—rules that, though unseen by most, are vital for global trade, resource management, and international peace. The law of the sea, he argues, "is one of the most important parts of international law and international relations," allowing nations to share the world's oceans fairly and safely.

For further community discussion, Gary encourages listeners to join the podcast’s Facebook and Discord groups (links in show notes).