I mean really. Are there actually people that think this?
Blunt siad he was voting against it because he thinks it isn't proper to vote on a treaty in a lame duck session. It has nothing to do with the excellent - if off target - analysis of the constitutionality of treaties. His no vote apparently has nothing to do with the language of the treaty.
The more thoughtful posters have read the OP's question and attemted to answer it by actually reading about what some senators have said, less thoughtful posters have said, "I said 'I don't know' That is an answer. I cannot change it." not realizing that the inability to try to know makes one stupid.
The bottom line is that the no vote has nothing to do with the content of the treaty, and everything to do with partisan politics.