Why have nato’s operations changed overtime? a. the simple goal of defending western europe got more complex after the cold war, and nato now responds to more diverse threats like humanitarian crises. b. their direct competition with united nations has evolved to lead to political actions c. the unity of the european union has demanded a stronger military force defend it d. when the us left nato after the end of the cold war and they had to revolve to focus on more humanitarian measures with the smaller budget