Each country owns territory on either side of a series of contested, and increasingly ice-free, Arctic straits. Russia considers the narrowest parts of the Northern Sea Route to be "internal waters." Canada takes the same view of the Northwest Passage. Internal waters are not territorial waters, and foreign ships have no right to access them without permission from the coastal state.
Russia and Canada face a single, common source of opposition to their claims — namely, the United States, which insists that both the Northern Sea Route and the Northwest Passage are "international straits."