But if history is any guide, the new canal could also compromise American naval power. American strategist Alfred Thayer Mahan, who is to naval theory what Einstein is to physics, emphasized ruling the ocean through control of select and narrow passages. The ocean itself is vast, but there are only so many places where a navy can cross between oceans, and these are tremendously important for maritime power and commerce. For example, the British Empire was able to control the Mediterranean with bases at the entrance in Gibraltar in the west and the Suez Canal in the east. Controlling the fastest, most direct route between the Atlantic and Pacific gave the United States a very strong position at a relatively low cost. A second canal, at best, complicates that.