Unless they were desperate? If we had any sort of conflict with Russia or China the first thing they would want to do is totally wipe out our space assets. The US military is so heavily dependent on satellites for reconnaissance , GPS, etc it would cripple core services of the US.
In the while china isn't a super power, it has no reason to go to war with the US. A war with china would turn into a nuke war, same with the US. If we had a reason to attack, we'd be flying satellites over them to find targets of strategic value before the declaration of war is signed.
Putin is a crazy man, but I don't think he is going to try and take on all of nato. The logistics it would take to invade the entire US is too great and invading Russia is a death sentence unless you have enough allies and logistics to handle it. China's navy is weak, but its large landlocked navy would make them a death sentence to invade as well.
Pretty much a war with either is a nuke fight. However we share the same weaknesses as our so called enemies, we all have a large dependence on technology.
Okay so you are telling me that we should send in a ground based scout to look for mobile ICBM's and other high value targets inside Russia or China? I don't think so, that's what the SR-72 was designed to do. You are totally confusing tactical reconnaissance with strategic, which are two totally separate things.
Like I say before, We'd be nuking missile silos, airfields, sub pens, and naval yards. You can't move those things easily. It is the job of the satellite to find those things.
Stuff like this:
and this
aren't too far behind enemy lines. In the gulf war we had scouts and helicopters behind Iraqi lines laser marking targets with laser beams for aircraft and missiles. Besides, the modern conventional war is about speed and maneuverability. These things would be gone by the time satellite or spy plane finds them, which why need something that can get in the area fast and maintain a small pressure. Put a spy plane in that area for too long and you risk it getting shot down.
The SR-72 travels at Mach 6 well above 120,000ft, which in theory would be in the combat envelope of the S-400. But a target flying at Mach 6 greatly reduces engagement time and the altitude also plays a factor. You also have to remember this thing would probably have a forget-load of ECM and active counter measures to ensure it's survival.
If we can make missiles that target satellites in space, we can make fast missiles that can hit things is space. Also remember the F-117. Most stealthy tactical bomber for its time? Got pinged by a stuffty old as soviet Radar and got downed by a really old missile in the Balkans?
Besides they can just keep trying to invent newer radar systems and missiles. No one wants to go through another gulf war, so every is out to try and compete with our tech by countering it.
