Export Restrictions: The Missing Disciplines

A student of mine has just submitted an interesting paper on the economic effects of, and legal disciplines on, export restrictions.  The case he has in mind is Chinese coke.  It appears that export restrictions have trade distorting effects symmetric with import restrictions. Of course, export prohibitions are illegal under Art. XI of GATT.  But, strangely (at least from an economic standpoint), export taxes are not illegal and are generally not disciplined.   There might have been an argument at one time that export taxes amount to a subsidy of the users of the input, but softwood lumber seems to have put an end to that.  On April 27, the EU proposed negotiations toward curbing export taxes.  See TN/MA/W/11/Add.6.