"Bait and Switch" on Treaties?

Ed Whelan at National Review Online's Bench Memos argues:

American transnationalists ... use a bait-and-switch game on "human rights" treaties. In urging that the United States adopt the treaties, they hide behind the treaty's grand and sweeping statement of a seemingly unobjectionable principle. Focused on the supposed concerns of a hypothetical world community, they trumpet the need for the United States to make an "important global statement" and to show that "our national practices fully satisfy or exceed international standards." Meanwhile, at the same time as the supervisory committee established by the treaty is interpreting the treaty to advance a radical agenda, American transnationalists obscure or dissemble about what the treaty committee is doing when they are speaking to the Senate and the American public — and then they turn around and use its interpretations to advance their agenda in courts.

I'm not sure of the intentions of the people involved; Whelan is criticizing Koh here, but that's not my goal with this post. But the intentions might not matter that much, because my sense is that this is indeed a potential danger, even if everyone's intentions are pure.

Whenever one is proposing adherence to a treaty, or the enactment of a statute, it's tempting to describe the proposal narrowly. Then once it's enacted, it's tempting to read this broadly. People being what they are, they fall into this temptation, and the rest of us may find the result to be a bait-and-switch even if it wasn't so intended.

And it strikes me that this is indeed a potential danger with a range of "human rights" treaties: We might indeed sign on to the text of a treaty because the text seems sensible, but then end up some years or decades later being stuck with international interpretations of the treaty that are much broader than the text suggests. To be sure, we could say "We signed on to the treaty's text, not its interpretations." But that might be a difficult argument to make, especially (1) when people are pressing us not to alienate the "international community," and (2) given that deference to judicial and even executive interpretations of domestic statutes — and not just to the statutory text — is an American legal norm.

But this is just a tentative judgment, based on my limited experience with the field. Can those of you who have more experience with these sorts of international treaties speak to this question?