Two weeks ago, a little-known Canadian gold mining company that has developed or operated exactly zero mines over 17 years announced to its investors that it had initiated international arbitration proceedings against the government of Romania for failing to permit what would be the largest open-pit gold and silver mine in Europe.
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.
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.