The article backs its focus on the sea with this often-cited fact:
But with 75 percent of the earth's population living within 200 miles of the sea, the world's military future may well be dominated by naval (and air) forces operating over vast regions. And to a greater extent than the other armed services, navies exist to protect economic interests and the system in which these interests operate.
It is true enough, I suppose, to say that 75% of the earth's population live within 200 miles of the sea. I'd also like to point out that 100% of those people living within 200 miles of the sea live on land. That's an equally interesting fact, no? And to a greater extent than the other armed services, armies exist to protect (or conquer, if you will) the land, its resources, and the people on it. We do not control the seas in order to control the seas.
I'm certainly a strong supporter of having a strong Navy. We need the seas to get anywhere, practically speaking. (No slight to Canada or Mexico intended.) But always remember that for America, controlling the seas is for the purpose of maintaining access to the land at the distant end of those sea lines of communication we protect.