Sunday pundits (the Mclaughlin Group) were waxing indignant about Russian submarine operations in the Atlantic. While I'd just as soon the Russians stayed in port and let 'em rust in peace, they do have a perfect right to steam in international waters. It's called freedom of the seas, and has been a big thing in US foreign policy reaching all the way back to Thomas Jefferson's administration.
Used to be, international waters started three miles offshore. We held to that standard for a long long time. Only in the 1980's did the US finally assert the right to control fishing for 200 miles offshore. Not sure if that included the right to exclude ordinary shipping or foreign navies that far out, but even so, the Atlantic is 3000 miles across, and most of it is still international waters.