Space Warfare?

So you hear about spy satelittes being up in space. US spy satts above Chinese airspace and vice versa. Since no one had jurisdiction over space, what stops China have blowing up US spy sats and vice versa?

>>1

If a tree in a forest falls and noone is there to hear it, does it makes a sound?

If a satellite is blown up in space and noone can hear it because there is no sound, does it actually blow up?