This might be another super utopian thought(like legalize marijuana) but if all the decades of 3D shooter games can have a positive impact on society that would definitely be moving wars into a realistic 3D shooter VR battlefield ready to accommodate any number of willing participants.
All states would have to agree on the virtual battle with real stakes formed of massive amounts of capital, basically any damage in virtual gets paid in the real, keeping the most adrenaline addicted veterans immersed in the game as if it was back in the napalm smelling days.
The army would divert funds into creating bigger and faster networks, computers, VR headsets and immersive displays.
Ammo makers would be coders in this case, as the war platform is open for plugins and virtual gadgets, imagination and virtual sky is the limit.
We are on this planet in this form potentially since over two hundred thousand years, hope we can sync up with the exponential curve technology is taking us on.