Democratic posturing for the Left Wing
Are we really to believe that the Senate Democrats don't know Democrat Obama's parameters for the trade deal, or don't trust him to sell them out? This is pure posturing for the benefit of the antiquarian anti-trade wing of their party.
In fact, it risks selling out their constituents, as the treaty may be negotiated by a Republican president, should it not be concluded by 2016. But posturing is what this constituency wants.