Various efforts to get Washington to carry out its NAFTA obligations
involved intense politicking during several U.S. administrations. After
many failures, a new “demonstration” program was scheduled to start
in April 2007 that would have permitted 100 Mexican trucking companies
to send trucks to destinations within the U.S. The program was
“defunded” by Congress, however, leading Mexico to impose a basket
of tariffs in retaliation (Frittelli, 2010).