Durability of Politics

I suppose that I am an idealist, as I still find it surprising that Senators Charles Schumer and Lindsay Graham can be taken seriously as they threaten China with a 27.5% tariff on imports unless China revalues the renminbi.  Why doesn't China simply say, well you know, Senators, that would be illegal, and send them on a tour of the Great Wall?  Instead, China is reported to give these Senators higher access than usual.  Further, and only slightly unrelated, today's FT reports that Karan Bhatia, deputy USTR, juxtaposed the need for Chinese currency flexibility with a warning that China should expect to be the target of new complaints at the WTO.