It's not just about shutting down other nations' satellites, even though that in itself is a huge thing to do in war because it can knock out communication. If you can drop weapons from space, such as tungsten rods, these bastards come without warning at Mach fucking ten. The physical evidence, ie the rods themselves, penetrate into the ground so deep that they cannot be retrieved. If you're lucky, you might see them in a single frame of cctv footage. If one nation can take out another nation's ports at will without any defensive response and without any means of proving who did it, that's worth more than knocking out communications. That's just the start. Next up will be space mining. Who gets to stake a claim to the water on the Moon, which then can be broken down into hydrogen and oxygen (fuel and air)? Whoever owns the Moon controls any space mission that relies on a fuel stop at the Moon. How long this is away is anyone's guess, it's probably not happening in our lives, but we'll see the first pawns being moved into place while we're alive.

The next great superpower will be whoever takes control of space first.