The most salient "add-on" feature of the TPP is its investor-state dispute settlement mechanism, which gives investors private rights of action against governments outside the court system. The problem is not so much that it violates rule of law and sovereignty, but that it shrinks the actual and potential role of the public.
Fast track is The Money directing Congress to go utterly against what vast majorities of people actively say, what movements of people are fighting for. Is this how business will be done in the 21st century? Maybe, but maybe not. We the People came close to winning this time. We will come closer and closer, then we will start winning again.
If the TPP's enforcement mechanisms were as toothless as those of labor side agreements or the ILO Declaration there would be no need for fast track. If the labor side agreements or the ILO Declaration had enforcement mechanisms as vigorous as those of the TPP I daresay the vote on fast track would be lopsidedly against.
Obama and Congressional Republicans have few areas of agreement. Opponents of their shared trade agenda seek to make that list shorter. Anti-trade advocates should question whether they are either blinded by an idealized partisanship that can only lead to paralysis, or captured by special interests at odds with the general welfare.