RealGM

I don't understand how players who were born outside the u.s like Nash and Dirk wouldn't be allowed to play for team USA but a player like Chris Kaman who was born in u.s to be eligible to play for Germany? or a guy like jr holden born in USA getting to play for Russia because he plays professionally in Russia and yet so do all these international stars like Nash and dirk but wouldn't be allowed to play for America, not that we need them or anything but I've always wondered. Anyone know why this is the case?

I think Nash and Dirk are allowed to play for US if they get their citizenship (Like Hammond did to be able to play in Russia), though they wouldn't want to play for the US, cause that would make them look bad for leaving their countries

It's very simple: FIBA rule states that if a player played for a national team of one country he can not play for another national team.
Hakeem never played for the Nigeran basketball team so he was allowed to play for USA. Dirk and Nash play for germany and canada from a young age and they can't play for USA, no matter what.
It also apllies for under-20 or under-18 national teams.
Joakim Noah, for example, can choose to play for Sweden, France or USA, but after he plays one game he can't play for a different national team.

Also, FIBA allows each national team to have only one "foreign" player at the same time (meaning someone who has citizenship, but not from birth), unless he got the citizenship before 18-17 years old.