Originally Posted by ofogs

Sure could. Systems such as FBCB2, which are everywhere, rely heavily on satellite systems. That's not the only system, but I'll use that as a representative example. Various HQs which are tracking fights and movements will be doing so on these systems. So are leaders in vehicles on the ground. It's a pretty good system and you get really good situational awareness and long range comms from it. The ability to operate dispersed but concentrate effects relies greatly on the network communications.

While a communictions or GPS outage would be measured in hours, the immediate effect would disrupt operations at all levels. HQs used to being able to see everything updated in near real time will lose almost all their SA and, often, their ability to communicate directly with that subordinate unit. Want to see a senior commander go into a tirade? Killing his ability to see the battlefield and talk to units is a great way to do it. Now, think about this happening at several echelons at a time.

Now, it's an adaptable military, for the most part, and eventually units will start breaking out the maps and using backup systems. Different units will do this at varying rates, but they'll eventually make it happen.

There would, in the interim, be a huge vulnerability. Everything would come back on line, eventually, but a well coordinated attack could create enough confusion to allow the decisive blow to be struck during the chaos. It's a lot like Oceans 11 (or 13). They didn't have to knock out the security system, they just needed to suppress it long enough to strike.