At least for myself, I think I tend to value world opinion in part
because I /want/ world opinion to matter. I want to live in a world where
countries communicate intelligently with each other, and great matters of
state are negotiated by smart people with the mandate of their citizenry.
That is much more important to me than isolationism, because I know that
isolating ourselves is just plain impossible in this era.
I'm also realistic enough to recognize that UN governance isn't worth
a pile of steaming dogshit unless the sole remaining superpower (you
know who) goes along with whatever they decide, and that's not going to
change unless the leadership of that same superpower wants to let that
change occur.
So if Kerry's telling the truth about wanting to work with other countries
(and Congress doesn't get in the way of doing so), then we may see the
UN start to matter again within a decade.