From the U.S. perspective, NAFTA and GATT are more powerful than TPP would be. Both address NTBs and were negotiated this way.
On top of that, international security agreements like NATO and the Anti-Ballistic Missile Treaty were negotiated this way, and those arguably have more serious import for a nation than trade.
On top of that, international security agreements like NATO and the Anti-Ballistic Missile Treaty were negotiated this way, and those arguably have more serious import for a nation than trade.