The part where the constitution requires 2/3 of the Senate to approve, but Fast track only requires a majority vote, and then not to approve, but to disapprove.
And the part where Congress can't amend or filibuster.
And the part where the bill is kept secret and pubic doesn't get to debate it.
Cruz has called for TPP to be released. Says there is no reason for it to be secret.
Any Trade Agreement made under TPP has to be made public for 60 days before Congress votes.