Yeah, while a lot of people seem to kind of brush the whole idea of a space force off as a big joke. I do kind of see a need to protect our satellites. They are just that important.
Imagine the hysteria if another country took out just a few of our communication sats. The headlines (which you probably wouldn't be able to view, at least easily) would be: "Why hasn't something been done to protect our satellites!"
What do you mean by "protect"?
Satellites are fragile and the involved velocities turn tiny objects into extremely destructive weapons. All you need is a cloud of particles whose trajectory crosses the satellite's at a sufficient angle. You can't "shoot them down" like an atmospheric object since there is no friction to stop them, nor a ground to crash into. Same reason why nukes won't protect us from asteroids.
Satellites aren't particularly agile either. Debris avoidance maneuvers like the ISS does take place far in advance of a potential collision. You won't achieve much in the few minutes it takes for the hostile rocket to reach LEO, and even at GEO I doubt that you'll be able to move far enough.
Protection against a capture would try to disable the approaching satellite without turning it into a cloud of debris (and before it has reached a collision course). So you don't want to use counter-missiles. Satellites are well hardened against radiation so high powered lasers are the only solution I see. Or precise, single bullets to take out its electronics. But you can't be too far away, or you won't reach the other satellite in time.
So how many "defender" sats would you envision? What about your opponent's inevitable "defenders"? Where do you draw the line between a "peaceful defender" and a "threatening aggressor"?
If you thought of some other "protection", please elaborate.