Johnny
A capital would have existing infrastructure in place that the new country can utilize.
Within the context of the game, they become important target sectors and, thusly, something over which countries can battle.
if the nation is deleted, i disagree. their bases would be abandoned if they removed their nation, and yet those disappear as well. within the context of the game, someone cannot simply delete a nation from the face of the earth. it would make more sense for a nation to be simply "abandoned", but that wouldn't allow new players to drop their nation in an area that an abandoned nation was occupying.
while this does allow a location to be fought over, i still think that it's broken, and is a solution that is unrealistic- even when you defend it.