&gt; The US Congress does, really, have line-item authority over regular US laws.<p>I don&#x27;t think legality was the issue.
The issue is that there are dozens of countries that need to vote on the same exact text for it to have an effect.<p>Surely the US Congress could modify it but then the other players will at best ratify a different version and at worse change items here and there themselves.<p>In both cases, what you get is not an international trade agrement.
You may as well vote &quot;no&quot; or not even try to negotiate a deal.