With respect to politicians in the U.S., a public choice argument would be 
that congressional representatives are elected from districts small enough 
to allow for coalitions of local businesses to lobby for, and buy, 
special-interest legislation--namely, measures that protect them from 
foreign competition. 
 
Senate politicians are elected state-wide and thus are less likely, but not 
altogether exempt from, local special interest lobbying.  This allows them 
to pretend to a more statesmanlike approach to international trade issues. 
I would expect their bribes to be larger. 
 
Presidents are subject to even more diffuse and conflicting lobbying, in as 
much as different regions may conflict in the positive and negative effects 
of import and export trade on regional businesses.  Presidents and their 
lackeys are also the world power brokers in dealing with the heads of other 
states, many of whom have a strong stake in the growth of their export 
trade.  Thus, they may pose as the most statesmanlike of the three groups, 
and probably rake in even more loot from the uncertainties of the special 
interest group members as to whose bread shall be buttered. 
 
So, presidents can pretend to globalism; senators can pretend to respond to 
the merits of pro and con arguments and congresscritters can pose as 
champions of their localities.  Everybody wins, except the sheeple. 
 
Sam Bostaph