The trickiness (and the whole reason fast track is a thing) is that Japan agreeing on A likely depends on the US agreeing on B (which depends on Vietnam agreein

The trickiness (and the whole reason fast track is a thing) is that Japan agreeing on A likely depends on the US agreeing on B (which depends on Vietnam agreeing on C) It's hard to do compromise if the compromise itself isn't voted in. And when you're talking about 12 Nations... OTOH breaking down legislation into smaller chunks to pass is definitely a good idea that isn't applied often enough (see immigration). Though that too can be tricky. For example you can't have the universal healthcare mandate without the preexisting condition refusal ban ( I have cancer and can't get health insurance , and now I'm being taxed??)