would be less likely to sign an agreement with China that did not have those standards. If Vietnam were adhering to those standards in order to be in TPP and China is not, China would have every advantage in such an agreement and Vietnam would have none. Plus I get the impression that the countries in east Asia that are a part of this are doing it largely to avoid being pulled totally into China's economic orbit.
I also agree that enforcement is the key in any of these agreements. Pretty words do not mean much in reality unless backed up by enforcement. (Just like domestic laws don't mean much if they are not enforced.) I do believe that enforcement is tricky, even if it is essential, if we are going to make progress on issues like labor rights and the environment.
I am sure many Vietnamese (and many Americans, Canadians, Mexicans, Japanese, etc.) will resent foreigners deciding that some labor or environmental practice does not meet TPP standards. Many conservatives and some liberals will cry "Those foreigners can't tell us what to do. What about our national sovereignty?" in order to preserve a national policy that weakens labor and/or is bad for the environment.
This agreement may well not have high enough labor and environmental standards or inadequate enforcement mechanisms for those standards, but some similar agreement at some point in time - hopefully in the not too distant future - is the best way to achieve progress. Unilateral action - that timeless republican favorite, again being espoused by the GOP leader (though of course not out of sympathy for labor rights or the environment) - won't get it done.