Very possibly bending to the terms of their potential lenders. Read the link. It's not what you think.
If we were to put our foot on the neck of the Federal Government and force them to adhere to their role, it wouldn’t be a problem.
While I agree with you in principle, there has never been an attempt to fix either the Supremacy Clause or the manner of treaty ratification. The people had that within their power all right, but they were never informed of the problem, to which they "allowed" the added insult of the language of the citizenship clause in the 14th Amendment.
Everything is ambiguous to the postmodern mind. The real problem is not the structure of the supremacy clause, as pointed out here by a competent legal analyst:
http://mikenew.com/treaties.html
As for your articles, it cannot be disputed that environmental treaties have been abused to undermine Constitutional protections, though as pox has pointed out there are remedies for this and the time is right to pursue them.
And your historical author makes many other worthwhile points. But the theory that some of our founders were in effect traitors, because they included the specific wording about treaties to intentionally frustrate the rights of the people protected in the remainder of the document, is an outrageous theory which is insupportable at best and certainly has not been helped by supreme court precedent, which still, on the whole, uses rational principles of statutory interpretation, which lead irresistibly to the premise that no single clause of the Constitution can ever be understood as abrogating all the rest, especially so because the grammar of the clause more easily supports treaties as subordinate to the Constitution anyway.