With tensions rising in the Persian Gulf, professor Chris Waters draws on his military experience to explain how water borders are defined -- and how multiple systems of definition can lead to conflict where both sides can be right in a territorial dispute. Chris is the instructor of Law 207/707, International Law.

If you enjoy the podcast, take a moment to subscribe! Sign up for our mailing list on the Certificate in Law site, and subscribe to this show on any of the major podcast platforms: Apple, Stitcher, Spotify and Google Play. Search for "Fundamentals" in your app of choice!

Theme music for Fundamentals by Megan Hamilton. Art for the podcast by Valérie Desrochers.  

Art by Val Desrochers (vesrochers.com)


Welcome to Fundamentals of Canadian Law

I'm Matt Shepherd. As comedian Steven Wright once said, "it's a small world, but I wouldn't want to paint it." The world's actually pretty big, which makes international law, by definition, a big subject. So we're fortunate to have Chris Waters teaching Law 207/707, International Law, in the Certificate in Law program. He's got a gift for breaking down complex issues in easy-to-understand ways. I've been grappling with recent headlines around drone conflict in the Persian Gulf, so I was grateful that Chris could stop by and unpack it with me. I also learned the word "sinuosity".

This podcast is also not legal advice and is being presented for informational purposes only.

Fundamentals of Canadian Law is brought to you by the Queen's Certificate in Law, the only online Certificate in Law offered by a law faculty in Canada. You can find out more at takelaw.ca.


00:00 Matt Shepherd: What has sparked your interest in international law? What brought you to us to teach this course in international law?

00:08 Chris Waters: Well, I'm a retired member of the armed forces, Canadian armed forces, and throughout my career I deployed quite often on exercise and operations overseas. And later in my career, I became a military lawyer. And in that role I had to advise the chain of command and the commanding officers on what the responsibilities and limits were when in foreign soil or crossing foreign boundaries, and that increased my interest in education. I did further education, and then I turned my attention, once I retired, to teaching. And here we are.

00:40 MS: And now you're here with us. So among the many things that you were instructing people on while you were with the military, you mentioned borders, and that's kind of the reason we're talking today is something happened in June. Iran shot down a US drone, and it's made international headlines. It's been in the news pretty much constantly since then. And just idly chatting with you a couple weeks ago, you told me some amazing things about borders that I wanted to kind get you to talk about now.

01:08 CW: Yes, and I would say it's an interesting incident because... Well, not just because it's being... Between two countries that are now in a state of tension, but also took part in a place in the world where borders are often contentious, and there are competing claims for sovereignty. And what struck me was that both countries, as is usually the case, made a claim that they're in the right. Well, can they both be in the right? And that's the question. Can a drone be in international airspace and domestic airspace at the same time?

01:43 MS: And clearly not, right? It's gotta be in international airspace or domestic. It can't be in both, right?

01:48 CW: Well, it depends on which nation claims which border and how they go about it. And I can explain that in some detail, but it's... Before we start, it's important to know that the drone is a weapon of war. And the drone in question was a reconnaissance drone which was seeking information, electronic or visual, from inside Iran. And the practice is to fly along borders with your sensors aimed into your opponent's country to gather all the intelligence you need. And it calls to mind, for those who remember the Cold War, the Russian trawlers sailing up and down the 12-mile limit off the East Coast of United States collecting intelligence, electronic intelligence. It's much the same but in a modern context.

02:35 MS: So it's kind of like the kids' game of, "I'm not touching you, I'm not touching you, I'm not touching you."

02:39 CW: Yes, and it's important to know that you can do certain things on the high seas or in international airspace which you cannot do in territorial water or in national airspace, and that's the key to this problem.

02:51 MS: So how does this idea of international space and domestic space... For what you're saying to be true, they have to overlap somehow, right? So how is that possible? How can the two of them stack on top of each other like that?

03:04 CW: Well, we have to go back to basics for that. And in international law, your boundaries are defined: Land, sea, and air by international convention or custom. Right now, you're talking about land and sea borders. Your territory over which you have complete control and sovereignty goes out to 12 miles into the water from your coastline from the lowest tide point. So you have 12 miles of turf, water, which belongs to you, which as a nation-state you can control for security, for environment, for trade and commerce, and that's where the problem begins.

03:54 MS: So I can go 12 miles from my lowest tide point out into the water and that's... Unequivocally, that's inarguably my territory?

04:03 CW: Yes, that is your territory. But there are different interpretations of how you measure the 12 miles, and that's why this incident has been claimed to be right by both sides.

04:14 MS: So how can this measurement differ? Twelve miles is 12... I'm a bit surprised it's not metric, first of all, but 12 miles is 12 miles is 12 miles, right?

04:22 CW: Not only that, it's 12 nautical miles.

04:24 MS: Okay.

04:25 CW: To do this, we have to do a little mental exercise. So close your eyes and pretend you're a seagull looking down at your nation's coast from above. Your coast is on the right and your water is on the left. You can see the ragged sinuosity of your coastline. And in normal situations, in international law, 12 miles from that point is your territorial boundary. Beyond that is the high seas, generally speaking, where there's freedom of navigation. Now also, for a control of airspace, the airspace boundaries follow the nautical and land boundaries. So you have to, as you're doing your seagull thing, raise your beak, look horizontally, and imagine a column of air rising above that 12-mile limit. Inside that is your national airspace. From there, you can control entry and egress, you can impose customs, security, defense, all those things that go with national sovereignty on any aircraft, friend or foe, coming into that airspace. Beyond the 12 miles is international airspace where, like the high seas, there's freedom of navigation.

05:42 MS: And at that point, you can put your sensors up and point them into that space, and you're not violating anything because you're not actually in the person's airspace.

05:50 CW: Correct. It's annoying to the country being surveilled, but it's not illegal.

05:54 MS: Right.

05:56 CW: So the difficulty arises in the different interpretation of the 12-mile limit. Now, there are two ways to measure. One is called the sinuosity method, where your 12-mile line exactly traces your coastline: The bays, the inlets, the promontories, the cliffs. And as a result, your baseline at 12 miles follows that exact profile. However, there's another approach. It's called the straight baselines method, also recognized in international law. And it says, you can draw a straight line from two points that jut out into the water to enclose a bay. So you can say that is now my territorial water because I drew the straight baseline from point to point enclosing that bay. Now, from a security point of view, that means your opponent cannot fly into that inlet to do surveillance or any offensive incident they wish to do. Think of Chesapeake Bay, Gulf of St. Lawrence, Bay of Fundy...

07:01 MS: So we're talking about bays that must, by definition, be larger than 24 miles across for this to make sense.

07:06 CW: Yes, well, there are limits, but not part of this discussion.

07:10 MS: Okay.

07:10 CW: But for the purpose of our incident in the Persian Gulf, it's important because depending on whether you take a baseline position or a sinuosity position, there is now a little area of gray zone which both sides claim to be either international airspace or national airspace. That's where the problem arises. Now, the Americans in the Gulf have, in recent past, taken the sinuosity view. They can sail to 12 miles from the coast of Iran, Iraq, and any of the areas there. Canada has a different approach. Canada has adopted the straight baselines approach and for a diplomatic and strategic reason: It's because we want to retain control of the Arctic Archipelago. And if we use the straight baselines method, it encloses all the islands around the Arctic, including the Northwest Passage, which means Canada can claim that to be sovereign territory and therefore control entry and exit into the Northwest Passage. Those who take the sinuosity approach or view it as an international seaway say Canada cannot control passage of international traffic through the Northwest Passage once it becomes clear because it's international transit.

08:25 MS: Because they're applying sinuosity and that doesn't... The sinuosity falls short of covering the entire space of the passage.

08:30 CW: Yes. Will let ships go through. And of course, ice is considered land when it's permanently frozen, but we're losing that advantage very quickly up there.

08:41 MS: So is there one approach that is... We've spoken about Iran's using the straight line, US sinuosity, we're using the straight line. Is there an approach that's winning internationally, is it... Are we ever gonna settle on one that's applied forever equally?

08:58 CW: Unfortunately, no. International law is like English grammar; there are as many exceptions as there are rules, so it's not a settled case. It depends... A nation claims a certain space. Canada has claimed the Arctic Archipelago, but it's just a claim. It has yet to be litigated in international court to say whether it's ours or it's international space.

09:20 MS: So what... There's... It's clear that there are two established and recognized systems for these boundaries, and it's clear that both countries... I don't know if you could say in good faith, I think there's a fair amount of animosity there, but they were definitely using legitimate measures of boundary. So do they just both eventually shrug and say, "Well, no harm, no foul," and go about their separate ways or...

09:49 CW: Well, I haven't heard what's going to be the outcome of this particular incident; it's gone off the news radar. We'll never know the true facts because they're obviously kept for operational security. But it happens all the while in conflict. We think about the shooting down of civilian airliners and mistakes made like that due to similar misunderstandings of international boundaries.

10:16 MS: I never knew any of this about international boundaries before. I thought things were just getting shot down and just kind of... It was too much fuss to do anything about it, and people just kinda let these things go.

10:26 CW: Well, interestingly, civilian traffic, civilian airliners are part of an international agreement: The Chicago Convention. They're not permitted to be shot down unless they pose a deliberate threat to the country. So there's freedom of traffic passage on the air routes for civilian airliners, but that doesn't guarantee their safety, as we saw from the Indonesia airline shot down in Ukraine a couple years ago.

10:52 MS: And there's other laws that affect things that pass through boundaries, so it could be important, I guess, for air travel to know where you're passing through, at what point, to make sure you're not violating any laws in transit.

11:03 CW: Yeah. And we have to be distinct between military operations, such as conducting surveillance, moving convoys, sailing through international straits with warships and submarines, than innocent civilian commerce or passenger traffic 'cause the rules do differ.

11:19 MS: Just getting a bit trivial, what happens when countries are separated by a body of water that's less than 24 miles wide?

11:26 CW: You meet in the middle, like lake Ontario.

11:28 MS: Right, just... You divide straight line down the middle?

11:31 CW: Yep.

11:31 MS: Or is it a sinuous line down the middle?

11:34 CW: It depends on the agreement between the nations.

11:35 MS: Okay. [chuckle] Boundaries are complicated.

11:39 CW: Well it... I'm glad you said that because if you think of the Northwest Passage, you may recall that Nixon negotiated an agreement. We agreed to disagree, between the US and Canada, about the use of the Arctic. They're gonna say, "Okay, we'll use the transit, but we'll inform you and you can monitor our progress."

12:00 MS: And we'd rather they just didn't.

12:03 CW: But it's an international agreement. It's a peaceful resolution, it's a compromise, and so far has worked. What we can't control, well, not yet, is the submarine passage, submerged submarines.

12:14 MS: Right.

12:15 CW: But surface traffic is easy to monitor and control with our surveillance up in the north.

12:19 MS: Chris, international law is super interesting.

12:22 CW: It is. It's fascinating, and it's a huge topic. And what people don't realize is that every time they pick up a paper or check their newsfeed on their handheld, there's something about international law. And we don't think about it, we don't think about the foreign airliners passing over us on the way to Toronto, we don't think of driving across the border to go to Watertown or whatever, but it's always there lurking in the background.

12:45 MS: Fascinating. Thanks so much, Chris.

12:47 CW: Very welcome.


Thanks to Chris Waters. International Law is a huge subject, including warfare, sovereignity, and much more, and we cover the essentials in Law 207/707, International Law. You can learn more about it at takelaw.ca.

Fundamentals of Canadian Law is recorded at Queen's University, situated on traditional [A NISH IH NAH BAY] and [HOE DEN OH SHOW NAY] territory. Our theme music is by Megan Hamilton, who is also a staff member here at Queen's Law! You can find out more about her music at meganhamiltonmusic.wordpress.com. Original illustrations for this podcast are by Valerie Desrochers. You can find her work at vdesrochers.com.

Thanks for listening.

Title Image Position Pinned to

50% 75%