It would take ~ 13 days for any single network partition for it to be mathematically possible for either partition to begin finalizing blocks assuming each partition contains 50% of the active validators each. Although this would require 100% of the validators in each partition to attest to the same blocks which would be very unlikely. Basically the only time we can realistically start finalizing blocks would be ~17 days.
I guess the assumption would be that if there were any WW3 event where the network was partitioned, it would be resolved in less than 17 days.