http://www.fpif.org/fpiftxt/2962#_edn11

The Federation for American Immigration Reform (FAIR) cites two primary reasons for concern about Mode 4. The group feels that Washington 's current offer of codifying existing provisions for H-1B and L-1 visas strips its power to restrict these programs in the future. For example, if there were a recession with mass layoffs of American workers, the U.S. government could not respond by lowering the number of such visas granted. Secondly, FAIR says that these types of visas “provide a major impetus to the outsourcing process, because the visa programs bring foreign workers to the United States , where they are trained in the operations of the company in order to facilitate outsourcing contracts with that company when they return abroad.” 11 There is anecdotal evidence that this is occurring but no data on the extent of the trend. The Center for Immigration Studies raises the additional concern that by including visa matters in the WTO, U.S. trade officials open the door for other countries to challenge U.S. immigration laws as barriers to trade in services subject to the WTO dispute resolution mechanism. 12