It won't get to that point because it's not needed. Behind the scenes Ethiopia will go back to sucking Egypt dīck. Aabo Egypt will spank his dark son Ethiopia on the futo and tell him he can finish his project. It won't have drastic implications on Egypt. Xaartopia knows Egypt can wipe Xaartopia from map in 1 day. Big lipped Bantus what can they do? What Bantu country can aid Ethiopia in a fight against Egypt which is destined to become one of the top 10 superpowers in the future.We'll see sxb. The African Union is headquartered in Addis. Egypt can't touch Ethiopia. All the Madows will rally for them.
I doubt it gets to that point. Egypt has been relying on an old colonial agreement that maintained their Nile water supply. If anything Ethiopia is going to demand money to make the problem go away.