When American companies act in their own best interest
In your opinion, who wields more domestic pressure on the international policy of a nation? It always depends on the issue, as far as I can see. If it is a globalization-related labor issue, expect the labor unions and multi-national corporations to get involved. If it is
military-related, like an arms treaty or the missile defense shield, expect the defense industry to have an opinion.
For example, the multi-national Wal*Mart has a lot to do with the fight against flotation of the Chinese yuan. A variable yuan, not pegged to the dollar but tradable on its own merits on the monetary exchanges, would inevitably rise. This would affect Wal*Mart's profit margins by raising the price of cheap Chinese consumer and electronic goods. So you can bet that Wal*Mart is lobbying Washington fiercely to back off pressuring China to float the yuan.
Sources:
Barker, Ned. "U.S. Trade with China: Expectations vs. Reality." PBS Online. Internet: Link, accessed 25 April 2006.
Lardy, Nicholas R. "The Economic Rise of China: Threat or Opportunity?" Federal Reserve Bank of Cleveland. Internet: Link, accessed 25 April 2006.