Right. I interpreted the original question as "what, ideally, would be the right thing to do?" as opposed to "what would you expect them to do?"
It's not really about the mere involvement of an economic treaty, that can certainly be a part of the negotiations. It's just that, in this particular situation, it's a blatant attempt to use our economic muscle to bend a smaller entity to our will on a completely unrelated matter. (Again, I don't find it surprising or unexpected in any way)
Well I'd argue the minimum proportional response to achieve the ends (i.e. there's some carrot/stick combinations that would not be 'right', or worth the international outcry... and even in that window why go for overkill?)
The problem is that I don't think the U.S. has a lot of carrots at any given time (what are we going to do, lodge a formal protest?), and you'd certainly not want to start off with the stick.
It's not really about the mere involvement of an economic treaty, that can certainly be a part of the negotiations. It's just that, in this particular situation, it's a blatant attempt to use our economic muscle to bend a smaller entity to our will on a completely unrelated matter. (Again, I don't find it surprising or unexpected in any way)