“And when Mexico says ‘no’ to U.S. troops being in their country, what would President Perry do? Considering that he made this proposal with absolutely no evidence whatsoever that Mexico might want U.S. intervention kind of indicates that their feelings aren’t of prime importance to him.”
You give Mexico certain options, and it just may turn out that what Perry proposes is not so bad to them.
Sure. Any Mexican president is going to sign off on hordes of gringo troops crawling all over his country. What's not to like about that?