Less international work equals cold relationships with other countries could damage vital relationships especially with those the U.S. needs for resources such as Saudi Arabia for oil.
The U.S. national interests could lead to conflict because frankly we are the world superpower, dominating in most aspects of trade and good, and for a small country like Pakistan to sell us oil, that would mean lots of money for them. What comes with the responsibility of earning our money also comes with competition with neighboring countries over the privilege to sell us oil.
