But I like to be critical, so I will go outside the stated scope a bit. The national security aspect of AI seems to go hand-in-hand with integration of drones and robotics. Because you won't have useful robots or drones until they are fully integrated with AI.
Assuming that cost-effectiveness and scale are actually concerns in manufacturing of military assets, China seems to have a significant edge as far as small drones and humanoid or animal-like robots.
Stepping back, the best solutions in my mind would involve somehow intellectually and practically reconciling the differing philosophies, cultures, and political systems, without first requiring mass scale destruction and casualties that force one group to capitulate for survival.
I'm not sure if that has historically ever occurred or could occur. But one might hope (probably as a fantasy) that somehow truly intelligent and general purpose AIs would be able to successfully convince their human clients in the military to skip the part where tens or hundreds of millions of humans work in earnest to successfully kill many millions of citizens from the other group.
I'd like to think optimistically that dramatically increasing energy availability could help lower global security tensions. So although I am honestly suspicious of Sam Altman's veracity and methods sometimes, I think his fusion plans are a great idea, and I really want to believe that they will pan out.