The TPP had very specific political goals - it created a common market for the US, a couple of Latin American countries, and most of the major East Asian and So

The TPP had very specific political goals - it created a common market for the US, a couple of Latin American countries, and most of the major East Asian and South Pacific economies... but NOT China. The idea being to both bind American allies in Asia more closely to it, and to ensure that if/when China wanted expanded trade with TPP members it would have to deal with rules that had originally been set by the US and its allies.