The main point is that binary (you achieve them or you don't) victory conditions won't work in a multiplayer timed game like DEFCON (or soccer, for that matter). Otherwise multiple people or even no-one could win.
One way of addressing that would be to assign a points value to each objective (a la old fashioned Warhammer)
e.g. 50 bonus points if [generic major city] isn't hit
Another way would be to have linear scoring based on the objectives
e.g. 1 point for every % population remaining in [generic major city]
Then it would be a fair contest to see who can defend the best (although I prefer the idea of making the objectives secret)
Cheers Tripper
(*) Cairo's no more difficult to defend than Tokyo, Mexico, even New York. After all, you can't park carriers and subs directly off shore ... It just tends to get hit first, is all.
(**) I played in one of Grim's games last night and I seem to remember that a "new" player put 3 silos around Cairo and nobody really bothered to nuke it because there were easier pickings elsewhere. I was SA, and I was too busy cleaning up the rest of Africa. Grim would know, he was Asia (please correct me Grim
)