Weren’t 2 Pandas a gift to President Nixon because of his trip to China?
Wow, I haven't thought of that term for 40 years!
Seriously, it's because they are so critically endangered.
At the present, there are licensing requirements and a ban on imports. Panda loans, if properly regulated, can be of tremendous benefit to conservation; however, bribes and illegal trade often override regulations.
Above is a snippet from an excellent article from Mandala Projects.